v24.01: (Upcoming Release)


Added spdk_trace_register_user_thread to initialize trace environment for an user created thread.

Modified spdk_trace_init to take number of user created threads as a parameter.


Added caw_iov field to struct spdk_scsi_task to support SBC-3 compare_and_write IO.

Added parameter delay to vhost_create_scsi_controller RPC which allows user to defer starting the vhost-scsi controller until adding the scsi target is completed.

Added vhost_start_scsi_controller RPC to start vhost-scsi controller, it could be used to support live recovery feature of vhost-scsi target.


Added support for SBC WRITE SAME 10 and SBC WRITE SAME 16.


A new transport option rdma_max_cq_size was added to limit indefinite growth of CQ size.


Added SPDK commandline parameter –no-huge, which enables SPDK to run without hugepages.


Added max_discard_size_kib and max_write_zeroes_size_kib to nvmf_create_subsystem to set the maximum discard size and maximum write_zeroes size.



Added spdk_accel_get_buf_align() API to get minimum buffer alignment to execute a given operation.

Added get_operation_info() callback for accel_modules to return constraints for a given operation.


Added spdk_bdev_open_async() API to allow asynchronous bdev open that waits for specified time until the block device appears.


Added bdev_nvme_enable_controller and bdev_nvme_disable_controller RPC to enable and disable NVMe controller. For NVMe multipath cntlid is used to select only one NVMe-oF controller.

Added cntlid field to bdev_nvme_reset_controller RPC to support resetting only one NVMe-oF controller in multipath configuration.


Added bdev_raid_remove_base_bdev RPC to remove a base bdev from existing raid bdev.


Updated DPDK submodule to DPDK 23.07.


The phys_addr parameter in spdk_*_malloc() functions is now invalid. Passing non-NULL value will return NULL from the functions. The parameter was deprecated in SPDK 19.04. For retrieving physical addresses, spdk_vtophys() should be used instead.


Added JSON-RPC 2.0 client written in Go to ease communication with SPDK. Please see the documentation at go/rpc/ and example at examples/go/.


Options for the JSON-RPC server initialization were added. The options are defined via the spdk_rpc_opts structure and is passed to the existing API spdk_rpc_initialize() as a new argument. The options include log_file and log_level.


Updated intel-ipsec-mb submodule to v1.4.


New APIs, spdk_jsonrpc_set_log_level and spdk_jsonrpc_set_log_file, were added to enable logging JSON RPC calls history.


New APIs, spdk_flog and spdk_vflog, were added to write messages to the specified log file.


The spdk_nvme_accel_fn_table interface has been extended with callbacks allowing users to chain multiple accel operations. Users can now send requests with an existing accel sequence by setting the accel_sequence field in spdk_nvme_ns_cmd_ext_io_opts if the controller supports it (i.e. sets the SPDK_NVME_CTRLR_ACCEL_SEQUENCE_SUPPORTED flag) and the user implements the necessary spdk_nvme_accel_fn_table callbacks.

The NVMe bdev will now advertise support for accel sequences if the allow_accel_sequence flag is set in bdev_nvme_set_options and the underlying controller also supports them.

The TCP transport will now calculate data digest using the accel sequence APIs if they're available.

Added spdk_nvme_qpair_is_connected() API to check the connection status.


The spdk_nvmf_request::data field has been removed: instead, clients should set ->iov and ->iovcnt appropriately, as nvmf request APIs now expect any data buffers to be described there. spdk_nvmf_request_get_data() has been removed.

transport field in listen_addresses of nvmf_get_subsystems RPC is deprecated. trtype field should be used instead. transport field will be removed in 24.01 release.

Added spdk_nvmf_subsystem_add_listener_ext() API for accepting new connections on the provided address, now allowing to specify additional options for the listener.

Deprecated spdk_nvmf_subsytem_any_listener_allowed() API (to be removed in 24.01) and replaced with spdk_nvmf_subsystem_any_listener_allowed()` API fixing the typo.

Added spdk_nvmf_subsystem_is_discovery() API to check whether a given susbystem is discovery subsystem.

Added new optional --ana-state (or shortly -n) parameter to nvmf_subsystem_add_listener RPC call.

scripts now supports interactive mode for device selection and hugepage reservation.

Added script that formalizes process of backporting commits from latest SPDK, to specific release branches. Please see documentation.


Added spdk_thread_is_app_thread() API to check if specified spdk_thread is the app thread.


Extended DIF support to CRC-32 and CRC-64 format of the Protection Information.

Added spdk_crc64_nvme() and spdk_crc32c_nvme(), CRC-64 and CRC-32C checksums compatible with NVMe Protection Information.



Added API spdk_accel_submit_xor to perform XOR.

Configuration of mlx5_pci driver of accel_dpdk_cryptodev module was changed. Now key and key2 should have equal length and key size in hexlified form can be either 32 bytes for 128b XTS key or 64 bytes for 256b XTS key. Support of the wrapped crypto credentials mode for this driver is dropped, only plain text mode is supported.

The accel library will now collect statistics on the number of executed operations and processed bytes. These statistics can be retreived using the accel_get_stats RPC.

Added support for appending a crc32 calculation to an accel sequence.


A new API spdk_bdev_module_claim_bdev_desc was added. Unlike spdk_bdev_module_claim_bdev, this function requires a bdev descriptor to be passed and the claim is automatically released when the descriptor is closed. It allows bdev modules to claim bdevs as a single writer, multiple writers, or multiple readers.

New APIs spdk_bdev_quiesce, spdk_bdev_unquiesce, spdk_bdev_quiesce_range and spdk_bdev_unquiesce_range were added. These allow I/O to be quiesced on an entire bdev or a specified LBA range.

Removed spdk_bdev_ext_io_opts from spdk_bdev_io and replaced it with fields that were missing in spdk_bdev_io.

It is now possible to submit an I/O with an associated accel sequence. All operations in such sequence will be executed prior to sending the I/O (writes) or after its completion (reads).


New functions spdk_env_get_main_core and spdk_env_get_cpuset were added.

It is now possible to run applications on cores with IDs greater than 128 by passing a core map using the --lcores parameter.


examples/nvme/perf application now accepts --use-every-core parameter that changes the existing worker and namespace association logic to access every namespace from each worker. This replicates behavior of bdevperf application when -C option is provided.


GPT bdevs now use the GPT Unique Partition ID as the bdev's UUID.




New API spdk_lvol_iter_immediate_clones was added to iterate the clones of an lvol.

New APIs spdk_lvol_get_by_uuid and spdk_lvol_get_by_names to get lvols by the lvol's UUID or lvstore and lvol names.

New bdev_lvol_get_lvols RPC to list logical volumes. This provides information about logical volumes without providing information about the bdevs. It is useful for listing the lvols associated with specific lvol stores and for listing lvols that are degraded and have no associated bdev.

Added support for external snapshots making it possible to create clones of any (including non-lvol) bdev. Users can create such clones using the bdev_lvol_clone_bdev RPC.


New API spdk_nvme_ns_get_format_index was added to calculate the exact format index, that was used to format the namespace.

Added two new APIs spdk_nvme_ns_cmd_io_mgmt_recv and spdk_nvme_ns_cmd_io_mgmt_send to receive and send the I/O management commands.


New spdk_nvmf_request_copy_to/from_buf() APIs have been added, which support iovecs, unlike the deprecated spdk_nvmf_request_get_data().

Two functions related to Asynchronous Event and error handling have been made public:

  • spdk_nvmf_ctrlr_async_event_error_event,
  • spdk_nvmf_ctrlr_abort_aer.

New spdk_nvmf_transport_create_async was added, it accepts a callback and callback argument. spdk_nvmf_transport_create is marked deprecated.

Parameters cb_fn and ctx of spdk_nvmf_qpair_disconnect API are deprecated. These parameters will be removed in 23.09 release.

Added a secure_channel parameter to the nvmf_subsystem_add_listener RPC. When true, all connections established via this listener will immediately attempt to establish a secure channel, prior to any authentication. Only valid for the TCP transport.

Added two optional transport module callbacks: subsystem_add_host() and subsystem_remove_host(). These functions will notify a transport about adding/removing hosts' access.

TLS PSK identity is now generated from subsystem NQN and host NQN. PSK interchange format is now expected as input, when configuring TLS in SPDK. TLS feature is considered experimental.


New API spdk_bdev_part_construct_ext is added and allows the bdev's UUID to be specified.


Added a zero copy receive interface allowing users to provide buffers to a socket group (via spdk_sock_group_provide_buf()), which will then get filled with the next portions of the stream on each socket. After that, pointer to the buffer holding the next part of the data can be obtained using spdk_sock_recv_next().

Added a callback get_key() to spdk_sock_impl_opts structure.

New function spdk_sock_get_impl_name() was added to retrieve current socket implementation name.


Added two new APIs spdk_thread_bind and spdk_thread_is_bound to bind or unbind spdk_thread to its current CPU core, and check bound status.


Enabled support for UBLK_F_NEED_GET_DATA. The buffers are no longer pre-allocated during initialization, but are allocated on-demand. Additionally, they're now allocated from the iobuf buffer pools.


New APIs spdk_uuid_is_null and spdk_uuid_set_null were added to compare and set UUID to NULL value.

Added new functions, spdk_fd_group_{nest,unnest}, providing efficient way of adding one fd_group's file descriptors to another fd_group.



New library isa-l-crypto has been added, it is used by accel library in crypto operations.

New functions spdk_accel_submit_encrypt and spdk_accel_submit_decrypt were added.

New accel module dpdk_cryptodev has been added. It uses DPDK crypto PMD and support encrypt and decrypt operations. New RPC dpdk_cryptodev_scan_accel_module has been added to enable this accel module.

New accel module mlx5 was added. It implements crypto operations, enabled when SPDK is configured with RDMA provider is mlx5_dv and crypto support.

Introduced the concept of chaining multiple accel operations together and executing them all in a single call. The operation can be chained via one of the spdk_accel_append_* functions and then executed using spdk_accel_sequence_finish. Currently, copy, decompress, decrypt, encrypt, and fill operations support this mode. This feature is considered experimental.


A new API spkd_bdev_part_submit_request_ext was added to specify a custom completion callback.

New APIs spdk_bdev_for_each_channel and spdk_bdev_for_each_channel_continue and associated function pointers were added to iterate each channel of the required bdev.

The RPC bdev_get_iostat now allows a user to query the per channel IO statistics for required bdev, and displays maximum and minimum latencies and I/O error counts.

New spdk_bdev_copy_blocks and spdk_bdev_get_max_copy APIs to support copy commands.

A new API spdk_bdev_io_get_submit_tsc was added to get the submit_tsc of the bdev I/O.

Bdevs will no longer have UUIDs generated based on timestamp and are responsible for setting this field themselves. Generation of UUIDs for NVMe bdevs may be enabled by running bdev_nvme_set_options RPC with --generate-uuids option. These identifiers are based on serial number and namespace ID and will always be the same for a given device.

A new API spdk_bdev_channel_get_histogram was added to get the histogram of a specified channel for a bdev.

Converted internal use of pthread_mutex_t to struct spdk_spinlock. Consumers of bdev API functions must be on an SPDK thread or the program will abort. It is now enforced that no internal bdev locks can be held when a poller or message goes off CPU.

A new RPC bdev_reset_iostat was added to reset I/O statistics of bdevs. Note that if one consumer reset I/O statistics, it affects all other consumers.

Add function pointers, dump_device_stat_json and reset_device_stat to the bdev module function table to display and reset I/O statistics specific for the module specific bdev context.

New APIs spdk_bdev_reset_io_stat, spdk_bdev_add_io_stat and spdk_bdev_dump_io_stat_json were added to process I/O statistics outside the generic bdev layer, especially in bdev modules.


vbdev_crypto is updated to use accel framework instead of DPDK PMDs.


New RPC bdev_daos_resize was added to allow resizing the daos bdev.


Both of interleaved and separated metadata are now supported by the malloc bdev module.

Protection information is now supported by the malloc bdev module.


Updated bdev_nvme_set_options RPC (and to support the new transport_tos parameter.

For the active-active policy of the multipath mode, in addition to the default round-robin path selector, the minimum queue depth path selector was added. The minimum queue depth path selector selects an I/O path according to the number of outstanding requests of each nvme qpair.

Added RPCs bdev_nvme_start_mdns_discovery, bdev_nvme_get_mdns_discovery_info and bdev_nvme_stop_mdns_discovery to perform Avahi based mDNS discovery service, as per NVMe TP 8009 - Automated Discovery of Ethernet Discovery Controllers.

A new option nvme_error_stat was added to the bdev_nvme_set_options RPC to enable collecting NVMe error counts.

Added I/O statistics per I/O path to the NVMe bdev module for NVMe bdev multipath. It can be enabled by a new option io_path_stat of RPC bdev_nvme_set_options.

Added RPC bdev_nvme_get_path_iostat to get I/O statistics for IO paths of the NVMe bdev.

Added selector parameter to bdev_nvme_set_multipath_policy RPC to set path selector for multipath. Option round_robin and queue_depth are available.

Added rr_min_io option to RPC bdev_nvme_set_multipath_policy. It switches I/O to another path after rr_min_io I/Os are routed to current io path for the round-robin path selector.

Added option --io-path-stat for RPC bdev_nvme_set_option to enable collecting io path stat.


Changed bdev_raid_get_bdevs RPC output format to include raid_bdev details.


Promoted the application to example to match similar programs: fio_plugin and perf. It can now be found inside examples/bdev/bdevperf.


Added spdk_mempool_mem_iter that allows to get start address and length of each memory chunk in order to create app-specific resources.


Added core lock file mechanism to prevent the same CPU cores from being used by multiple SPDK application instances.

Added --disable-cpumask-locks command line switch to disable CPU locks on SPDK startup.

Added RPCs framework_enable_cpumask_locks and framework_disable_cpumask_locks to enable and disable CPU core locks in runtime.

Added --rpcs-allowed command line option. Users can specify a comma-separated list of RPC names with this option to restrict allowed RPCs to only that list.

Added --vfio-vf-token command line option to specify a VF token (UUID) shared between SR-IOV PF and VFs for vfio_pci driver.

The spdk_iov_xfer_*() APIs were added for handling incremental copying between an iovec and a buffer.


Added API spdk_json_write_double and spdk_json_write_named_double to allow for writing and decoding of the the double data type.


Added consistent tracking of use of deprecated behavior. Deprecations continue to be listed in and now are in subsections with headers matching a tag used in SPDK_LOG_DEPRECATED() calls. When deprecated behavior is used, these tags will appear in SPDK's log at the warn level. As the SPDK application exits, it will log a summary of how many times SPDK_LOG_DEPRECATED() was called for each tag that was logged at least once.


NVMe transport options were newly introduced. The NVMe transport options are defined via the spdk_nvme_transport_opts structure and configured via spdk_nvme_transport_get_opts and spdk_nvme_transport_get_opts functions.

Shared receive queue was supported by the RDMA transport. It can be configured by a new NVMe transport option rdma_srq_size.

Added transport_tos to spdk_nvme_ctrlr_opts to support setting of the "type of service" value in the IPv4 header. Only RDMA is supported at this time.

Added API spdk_nvme_qpair_get_num_outstanding_reqs to get the number of outstanding reqs of a specified qpair.


Added API spdk_nvmf_tgt_pause_polling and spdk_nvmf_tgt_resume_polling to allow pausing polling on poll group of a given target.

The num_shared_buffers option now controls the maximum number of buffers a transport will pull from the central iobuf pool. It will not allocate additional memory. If the requested amount cannot be satisfied, a warning will be displayed to increase the size of the iobuf pool.


Added spdk_rpc_set_allowlist to restrict allowed RPCs to the specified list.


Changing scheduler from dynamic back to static is no longer possible, as there is no way of saving original SPDK thread distribution on reactors.


Added spdk_thread_get_app_thread which returns the first thread that was created using spdk_thread_create.

Added spdk_thread_is_running. This returns true for a running thread, or false if its exit process has started using spdk_thread_exit.

Added API spdk_spin_init, spdk_spin_destroy, spdk_spin_lock, spdk_spin_unlock, and spdk_spin_held to support spinlocks that are aware of the SPDK concurrency model.

Added iobuf buffer pool, set of API calls for allocating data buffers across libraries. Please see new API spdk_iobuf_*.


New trace_get_info RPC was added to get name of shared memory file, list of the available trace point groups and mask of the available trace points for each group.

ublk device

The ublk application supports the ublk kernel driver. It's implemented as a ublk backend in spdk_tgt and could be started with specifying configuration. See the ublk documentation for more details.

ublk bdev could export a block device via Linux ublk. It will move this backend device into userspace as /dev/ublkb*. Before to adding ublk device, need to create ublk target by RPC method.


New API spdk_fd_group_get_epoll_event that returns the epoll(7) event that caused a function callback in file descriptor group to execute.

Added API spdk_strarray_from_string, spdk_strarray_dup and spdk_strarray_free for handling arrays of strings.

A new API spdk_strcpy_replace was added to replace all occurrences of the search string with the replacement string.

New API spdk_iov_memset() was added to memset an iovec.

New API spdk_iov_one() was added to initialize an iovec for a single buffer.



Many names were changed in the accel framework to make them consistent both with themselves and the rest of SPDK. The primary public header file is now named include/spdk/accel.h.

Added a new runtime RPC accel_get_opc_assignments to get a list of current opcode to engine assignments.

Added a new startup RPC accel_assign_opc to assign/override a specific opcode to an engine.


New RPCs bdev_xnvme_create and bdev_xnvme_delete were added to support the xNVMe bdev.

A new API spdk_bdev_for_each_bdev_io was added to execute the function on the appropriate thread for each bdev_io submitted to the bdev.

A new API spdk_bdev_get_current_qd was added to measure and return the queue depth from a bdev. This API is available even when queue depth sampling is disabled.

Added spdk_bdev_seek_data, spdk_bdev_seek_hole and spdk_bdev_io_get_seek_offset functions that start from a given offset and seek for next data or for next hole. At this time only supported by lvol bdev module.

A new parameter io_drain_timeout has been added to spdk_bdev structure. It controls how long a bdev reset must wait for IO to complete prior to issuing a reset to the underlying device. If there is no outstanding IO at the end of that period, the reset is skipped. Best defined for bdevs that share an underlying bdev, such as multiple lvol bdevs sharing an nvme device, to avoid unnecessarily resetting the underlying bdev and affecting other bdevs that are sharing it. Modifying this field is optional. Setting the value to 0 keeps the original behavior to always send resets immediately, even if there is no I/O outstanding.


Reserve space for used_clusters bitmap. The reserved space could be used for blobstore growing in the future.

Added is_zeroes operation to spdk_bs_dev. It allows to detect if logical blocks are backed by zeroes device and do a shortcut in copy-on-write flow by excluding copy part from zeroes device.

Added spdk_blob_get_next_allocated_io_unit and spdk_blob_get_next_unallocated_io_unit functions that start from a given offset and seek for first io_unit belonging to an allocated cluster or first io_unit belonging to an unallocated cluster.

Added spdk_bs_grow function to grow blobstore size if the underlying bdev size is increased. This is used by lvol bdev via bdev_lvol_grow_lvstore RPC.


Added new DAOS bdev module, that creates SPDK block device on top of DAOS DFS. Please see documentation for more details.


Added spdk_pci_register_device_provider and matching SPDK_PCI_REGISTER_DEVICE_PROVIDER functions for registering PCI device providers. That allow the VMD driver to be notified when users want to attach a device under a given BDF and when a device is detached.


spdk_subsystem_init_from_json_config now fails if the JSON configuration file is not an object with an array named "subsystems".


Added bdev_iscsi_set_options RPC to modify options of the iSCSI bdev module.


Added spdk_json_find API return errcode: EPROTOTYPE - json not enclosed in {}. spdk_json_find now returns -EPROTOTYPE instead of -ENOENT if the object parameter does not point to a JSON object (i.e. is not enclosed with {}).


Add num_md_pages_per_cluster_ratio parameter to the bdev_lvol_create_lvstore RPC. Calculate num_md_pages from num_md_pages_per_cluster_ratio, and pass it to spdk_bs_opts.


Added SPDK_NVME_TRANSPORT_CUSTOM_FABRICS to enum spdk_nvme_transport_type to support custom fabric transport. SPDK_NVME_TRANSPORT_CUSTOM was intended to be non-fabric custom transport.

Added a new function spdk_nvme_ns_cmd_verify to submit a Verify Command to a Namespace.

Added spdk_nvme_ctrlr_disable_read_changed_ns_list_log_page to allow an application to tell the driver to not read the CHANGED_NS_LIST log page in response to a NS_ATTR_CHANGED AEN. When called the application is required to read this log page instead to clear the AEN.

Added psk field to spdk_nvme_ctrlr_opts struct in order to enable SSL socket implementation of TCP connection and set the PSK. Applicable for TCP transport only.


Renamed the raid5 module to raid5f to reflect that it is not a traditional RAID5 implementation - only full stripe writes are supported, partial stripe writes (read-modify-write) are not.


Added psk parameter to bdev_nvme_attach_controller RPC in order to enable SSL socket implementation of TCP connection and set the PSK. Applicable for TCP transport only.

New options enable_ktls and tls_version were added to the sock_impl_set_options structure. New options psk_key and psk_identity were added to the sock_impl_set_options structure.

Added warning message for bdev_rbd_create, if it is used without -c. bdev_rbd_create() API without specifying -c is deprecated and will be removed in future release.

Renamed enable_vmd RPC to vmd_enable to make it consistent with our naming scheme of <subsystem>_<action>. For now, the old name is still available, but is marked as deprecated.

New function spdk_rpc_get_method_state_mask was added to RPC library.


Extended VolumeParameters with crypto parameters allowing the user to configure crypto when attaching a volume to a device. This interface is now supported by all upstream device types (nvmf-tcp, virtio-blk, vfio-user) using bdev_crypto. Users must specify the crypto engine to use under crypto section in config. It is also possible to register out-of-tree crypto engines by inheriting from the CryptoEngine class.

Added two new methods: SetQos and GetQosCapabilities allowing the user to configure QoS on a per-device or per-volume level. Not all QoS settings have to be supported by each device, so users can use GetQosCapabilities to query them for that. All upstream device types support QoS on a per-volume level using bdev layer's QoS mechanism.


Added new ssl based socket implementation, the code is located in module/sock/posix. For now we are using hard-coded PSK and only support TLS 1.3.


Added new functions: spdk_hexlify and spdk_unhexlify.

A new API spdk_xor_gen was added to generate XOR from multiple source buffers. It is going to be used by raid5f for calculating parity.


Added vfu_tgt library abstraction based on libvfio-user for PCI device emulation. Besides the NVMe device emulation, its now possible to emulate virtio-blk and virtio-scsi devices.


virtio-vhost-user no longer tries to support dynamic memory allocation. The vhost target does not support the high rate of SET_MEM_TABLE vhost messages that result from dynamic memory allocation, so a virtio-vhost-user device will now present an ERRLOG, assert, and skip the SET_MEM_TABLE vhost message if a memory notification is received outside of the normal device start/stop. Applications using the virtio library in vhost-user mode should now pre-allocate the application's memory using the -s/–mem-size option and use single shared memory file segments using the -g/–single-file-segments option.

Added vfio-user transport type for virtio-blk and virtio-scsi devices.


Fixed hotplug when a device is inserted in a slot in which a disk was already enumerated previously. Added two new RPCs: vmd_remove_device simulating a hotremove, and vmd_rescan, which rescans all buses managed by the VMD driver and hotplugs all newfound devices.



A new option ack_timeout was added to the spdk_sock_opts structure.


A new parameter bounce_iovcnt was added to spdk_dif_generate_copy and spdk_dif_verify_copy. The bounce_iovcnt is used to specify the number of bounce_iov to support multiple block-aligned fragment copies.

A new API spdk_copy_iovs_to_buf and spdk_copy_buf_to_iovs were added to copy iovs to buf or copy buf to iovs. There're many cases need to use these two APIs.


Removed deprecated spdk_bdev_module_finish_done(). Use spdk_bdev_module_fini_done() instead.

A new API spdk_bdev_unregister_by_name was added to handle race conditions correctly.

New APIs, spdk_for_each_bdev and spdk_for_each_bdev_leaf, were added to provide iteration safe for race conditions.

A new RPC bdev_nvme_get_io_paths was added to get all active I/O paths.

A new RPC bdev_nvme_set_preferred_path was added to set preferred I/O path for an NVMe bdev when in multipath mode. This RPC does not support NVMe bdevs in failover mode.

A new RPC bdev_nvme_set_multipath_policy was added to set multipath policy of a NVMe bdev in multipath mode.

A new option disable_auto_failback was added to the bdev_nvme_set_options RPC to disable automatic failback.

idxd / dsa

A new parameter flags was added to all low level submission and preparation APIs to enable the caller to pass operation flags per the DSA specification.

A new flag 'SPDK_IDXD_FLAG_PERSISTENT' was added to let DSA know that the destination is persistent.

The RPC idxd_scan_accel_engine has been renamed to dsa_scan_accel_engine

The RPC iaa_scan_accel_engine has been added.

Many HW related structs/functions with the name idxd have been renamed dsa to more accurately represent the HW they are associated with.

Two new functions were added to the library spdk_idxd_submit_compress and spdk_idxd_submit_decompress


A new parameter flags was added to accel API. The APIs include: spdk_accel_submit_copy spdk_accel_submit_dualcast spdk_accel_submit_fill spdk_accel_submit_copy_crc32c spdk_accel_submit_copy_crc32cv spdk_accel_submit_compress spdk_accel_submit_decompress

A new flag ACCEL_FLAG_PERSISTENT was added to indicate the target memory is PMEM.

The API spdk_accel_get_capabilities has been removed.


Support for AES_XTS was added for MLX5 polled mode driver (pmd).

bdev_crypto_create RPC now requires hexlified 'key' and 'key2' params for all pmd drivers. Unhexlifying is performed during RPC command processing and the vbdev crypto module runs on binary keys as before.


Added a timeout option to the bdev_get_bdevs RPC. It allows the user to specify the amount of time to wait until a bdev with a given name appears in the system.


Added bdev_nvme_add_error_injection and bdev_nvme_remove_error_injection RPCs to add and remove NVMe error injections.

New parameters, ctrlr_loss_timeout_sec, reconnect_delay_sec, and fast_io_fail_timeout_sec, are added to the RPC bdev_nvme_set_options. They can be overridden if they are given by the RPC bdev_nvme_attach_controller.


New functions spdk_blob_io_writev_ext and spdk_blob_io_readv_ext are added. The new functions accept spdk_blob_ext_io_opts structure with extended IO request options.


Added msg_mempool_size parameter to spdk_reactors_init and spdk_thread_lib_init_ext. The size of g_spdk_msg_mempool can now be controlled through the same-named user option of spdk_app_opts structure.


The API spdk_nvme_ctrlr_prepare_for_reset() was deprecated. The functionality provided by the spdk_nvme_ctrlr_prepare_for_reset() was merged into the API spdk_nvme_ctrlr_disconnect().


Removed deprecated max_qpairs_per_ctrlr parameter from nvmf_create_transport RPC. Use max_io_qpairs_per_ctrlr instead.

Deprecated the ability for hosts to connect to the discovery subsystem automatically on any existing listener. Users should now explicitly add listeners for the discovery subsystem. Host can still connect to the discovery subsystem as before, but a warning message will be emitted if no listener was configured for the transport ID of the incoming connection.

Added adaptive interrupt feature for vfio-user transport. New parameter disable_adaptive_irq is added to the RPC nvmf_create_transport.


Added spdk_thread_exec_msg() API.


framework_set_scheduler can now be called after application initialization. Added callbacks to set custom parameters specific for each scheduler implementation and framework_get_scheduler to retrieve them.

Added dynamic scheduler options: load_limit, core_limit, core_busy. Their descriptions are available in JSON-RPC document, in section framework_set_scheduler.


Add concat as a special raid module. The concat module could create a virtual bdev. The virtual bdev combines multiple underlying bdevs together. The layout of the underlying bdevs is one after another. The concat bdev is extendable. When the free space of the concat bdev is not enough, the user can deconstruct the concat bdev, then reconstruct it with an additional underlying bdev.


Allow MSG_ZEROCOPY flag to be set or not according to data size, which can be enabled and set by setting "zerocopy_threshold". zerocopy_threshold = 0 means disable this function; zerocopy_threshold > 0 means enable it and use this value as the threshold.


Introduced zerocopy_threshold to enable zerocopy on send for server sockets according to data size to be flushed.



The batching capability was removed. Batching is now considered an implementation detail of the low level drivers.


The NVMe bdev module supports multipath and improved I/O error resiliency.

The parameter retry_count of the RPC bdev_nvme_set_options was deprecated and will be removed in SPDK 22.04, and the parameter transport_retry_count is added and used instead.

An new parameter bdev_retry_count is added to the RPC bdev_nvme_set_options.

New parameters, ctrlr_loss_timeout_sec, reconnect_delay_sec, and fast_io_fail_timeout_sec, are added to the RPC bdev_nvme_attach_controller.

An new parameter num_io_queues is added to bdev_nvme_attach_controller RPC to allow specifying amount of requested IO queues.

Added key_file parameter to the rbd_register_cluster RPC. It is an optional parameter to specify a keyring file to connect to a RADOS cluster.

Added spdk_bdev_get_zone_id API to retrieve zone_id for a certain LBA.


Added bdev_aio_rescan RPC to allow rescanning the size of aio bdev.


Added discovery service to bdev_nvme module, which now can connect to a discovery controller. bdev_nvme will connect to all current and future subsystems in the discovery controller. Added bdev_nvme_start_discovery and bdev_nvme_stop_discovery RPC.


Updated DPDK submodule to DPDK 21.11.


Added spdk_pci_for_each_device.

Removed spdk_pci_get_first_device and spdk_pci_get_next_device. These APIs were unsafe, because they did not account for PCI devices being inserted or removed while the caller was using handles returned from these APIs. Existing users of these APIs should switch to spdk_pci_for_each_device instead.

Added 3 experimental APIs to handle PCI device interrupts (spdk_pci_device_enable_interrupt, spdk_pci_device_disable_interrupt, spdk_pci_device_get_interrupt_efd).

Added framework_get_pci_devices RPC to list PCIe devices attached to an SPDK application.


Many APIs are now vectored rather than scalar, meaning they take iovecs instead of individual pointers.


Added spdk_json_write_bytearray API to serialize a buffer as a hex string.


API spdk_nvme_trtype_is_fabrics was added to return existing transport type is fabric or not.

API spdk_nvme_poll_group_remove was limited to be available only for a disconnected qpair in the group.

New APIs, spdk_nvme_ctrlr_disconnect, spdk_nvme_ctrlr_reconnect_async, and spdk_nvme_ctrlr_reconnect_poll_async, have been added to improve error recovery, and the existing APIs,spdk_nvme_ctrlr_reset_async and spdk_nvme_ctrlr_reset_poll_async were deprecated.

Added spdk_nvme_ctrlr_get_discovery_log_page API for getting the full discovery log page from a discovery controller.


Added support for zero-copy operations in the NVMe-oF TCP target. It can be enabled via the zcopy parameter when creating a transport. The zero-copy operations are only used for requests not using in-capsule data.

Added a subsystem parameter to spdk_nvmf_transport_stop_listen_async. When not NULL, it will only disconnect qpairs for controllers associated with the specified subsystem.

Removed accept poller from transport layer. Each transport can have its own policy of handling new connections. To notify transport layer spdk_nvmf_poll_group_add and spdk_nvmf_tgt_new_qpair can be used.


Structure spdk_scsi_lun has been extended with new member resizing so that SCSI layer now reports unit attention for disk resize.


Added spdk_trace_create_tpoint_group_mask to return tracepoint group mask from a tracepoint group name.

Added trace_set_tpoint_mask and trace_clear_tpoint_mask RPC to allow enabling individual traces.


Added spdk_ioviter_first and spdk_ioviter_next to iterate over two iovecs and yield pointers to common length segments.


A new parameter hint is added to spdk_sock_get_optimal_sock_group. It allows to suggest a poll group when no optimal poll group is found.


Structure spdk_nvmf_target_opts has been extended with new member discovery_filter which allows to specify filtering rules applied during discovery log generation. Refer to enum spdk_nvmf_tgt_discovery_filter for more info.


New API spdk_bdev_get_memory_domains has been added, it allows to get SPDK memory domains used by bdev.

New API functions spdk_bdev_readv_blocks_ext and spdk_bdev_writev_blocks_ext have been added. These functions accept spdk_bdev_ext_io_opts structure with extended IO request options, e.g. DMA memory domain which describes data that may belong to another memory domain and can't be accessed directly.

Added async_fini_start to allow bdev modules to complete the fini_start asynchronously, with new spdk_bdev_module_fini_start_done API.

Deprecated spdk_bdev_module_finish_done() API, which will be removed in SPDK 22.01. Bdev modules should use spdk_bdev_module_fini_done() instead.

The ocssd bdev has been removed. The Open Channel specification has been largely superseded by zoned namespaces, few if any devices have been brought to market, and there is little reason to continue to support this. OCSSD support in the nvme driver will remain for now.


A new library, lib/dma, has been added. This library provides the necessary infrastructure for handling systems and devices with multiple memory domains. For example, a PCIe add-in card with an SoC may be running SPDK on the SoC. That SoC has its own local memory, but SPDK may be controlling devices that can also access the host system memory. This library provides infrastructure to enumerate the memory domains and request hardware perform DMA transfers between them.


Updated DPDK submodule to DPDK 21.08.


Added the disable_signal_handlers flag to the spdk_app_opts struct.


Added spdk_idxd_get_socket to query the socket that the idxd device is on.


Added API to allow for writing and decoding of new types:

  • spdk_json_write_named_uint16
  • spdk_json_write_named_uint8
  • spdk_json_write_uint16
  • spdk_json_write_uint8
  • spdk_json_number_to_uint8
  • spdk_json_decode_uint8


Added API spdk_log_to_syslog_level to return syslog level based on SPDK's log level.


Added new functions spdk_nvme_zns_set_zone_desc_ext and spdk_nvme_zns_ext_report_zones to set zone descriptor extension and to get extended zone report respectively.

New API spdk_nvme_ctrlr_get_memory_domains has been added, it allows to get SPDK memory domains used by nvme controller.

New API functions spdk_nvme_ns_cmd_readv_ext and spdk_nvme_ns_cmd_writev_ext have been added. These functions accept spdk_nvme_ns_cmd_ext_io_opts structure with extended IO request options, e.g. DMA memory domain which describes data that may belong to another memory domain and can't be accessed directly.

Added a new function spdk_nvme_ctrlr_get_regs_bpinfo to get boot partition info of a controller. Added new functions spdk_nvme_ctrlr_write_boot_partition, spdk_nvme_ctrlr_read_boot_partition_start and spdk_nvme_ctrlr_read_boot_partition_poll to write and read the boot partitions of a controller.

Added spdk_nvme_ctrlr_get_opts to retrieve the current controller options.

Added async_mode to spdk_nvme_io_qpair_opts to enable creation of submission and completion queues asynchronously. This mode is currently supported at PCIe layer, which tracks the qpair creation with state machine and returns to the user immediately. Default mode is set to false to create io qpairs synchronously.

Added spdk_nvme_ctrlr_get_regs_cc to retrieve NVMe controller CC (Configuration) register.

Added spdk_nvme_ctrlr_prepare_for_reset to inform the driver that the application is preparing to reset the specified NVMe controller. This function allows the driver to make decisions knowing that a reset is about to happen.


Added oncs to struct spdk_nvmf_ctrlr_data so that the transport layer can decide support RESERVATION feature or not.

An opts_size element was added in the spdk_nvmf_ns_opts structure to solve the ABI compatibility issue between different SPDK version. An new option anagrpid was added in the spdk_nvmf_ns_opts structure.

An new parameter anagrpid was added to the RPC nvmf_subsystem_add_ns.

An new parameter anagrpid was added to the RPC nvmf_subsystem_listener_set_ana_state.

spdk_nvmf_subsystem_destroy is now can be asynchronous, it accepts a callback and callback argument.

A new parameter, poll_groups_mask was added to the nvmf_set_config RPC that allows specifying a subset of cores for the nvmf poll groups. This helps to avoid imbalances when some cores are busy with periodic timer tasks that run very frequently.

A new parameter, commit was added to nvmf_bdev_ctrlr_end_zcopy that allows indicating whether the buffers should be committed.

Added listen_dump_opts to spdk_nvmf_transport_ops so that the transport layer can display listen opts.

Added fabrics_connect_timeout_us to bdev_nvme_attach_controller RPC to allow specifying timeout for connect operation.

Added multipath to bdev_nvme_attach_controller RPC to allow specifying multipath behavior.


New API for implementing schedulers and governors. Please see include/spdk/scheduler.h for details.


New functions, spdk_scsi_dev_get_first_lun and spdk_scsi_dev_get_next_lun have been added to iterate LUNs of a SCSI device.

Each SCSI device supports 256 LUNs at the maximum now and the macro constant SPDK_SCSI_DEV_MAX_LUN was removed.


A new library, lib/trace_parser, has been added. This library provides functions that parse traces recorded by an SPDK application. That includes merging traces from multiple cores, sorting them by their timestamp and constructing trace entries spanning across multiple buffers.


The spdk_fd_group_add API now takes a name parameter.



Added API spdk_accel_submit_copy_crc32c to perform a CRC32C while copying data.

Added API spdk_accel_batch_prep_copy_crc32c to batch CRC32C + copy commands.

Added API spdk_accel_submit_copy_crc32cv to submit chained CRC32C + copy commands.


Change spdk_bdev_read_blocks_with_md arg offset definition from int64_t to uint64_t.

Red-black tree has been used to organize the bdev names and aliases uniformly to provide faster lookup.

Removed ZCOPY emulation: The bdev module can be checked to see if it supports ZCOPY and if not supported then use existing READ/WRITE commands.

Added iov to spdk_bdev_zcopy_start.


Updated DPDK submodule to DPDK 21.05.


Remove the probe_cb parameter in spdk_idxd_probe function. And remove the definition of spdk_idxd_probe_cb function pointer. It should be implemented in idxd_user.c.

Added API spdk_idxd_submit_copy_crc32c to perform a CRC32C while copying data.

Added API spdk_idxd_batch_prep_copy_crc32c to prepare a batch operation to perform a CRC32C while copying data.

We have userspace idxd driver under accel_engine library (module/accel/idxd/accel_engine). And kernel idxd driver usage is also added under the accel_engine library. This approach implemented a wrapper library to use IDXD device by leveraging the kernel DSA driver in SPDK idxd library (lib/idxd). Then users can leverage the RPC later to configure how to use the DSA device by user space driver or kernel driver.


Added new init library that initializes the SPDK subsystems, which previously was internal to application framework. That functionality has been made public and for use by applications which don't leverage SPDK's application framework.


New parameters, pdu_pool_size, immediate_data_pool_size, and data_out_pool_size, were added to the RPC iscsi_set_options to run iSCSI target with varying amount of available memory.


Added API spdk_json_write_named_uint128 and spdk_json_write_uint128 to perform the uint128 related data.


Removed deprecated net library.

Added support for ZCOPY. ZCOPY is used in preference to READ and WRITE if the bdev module supports ZCOPY and the bdev module has ZCOPY enabled.


spdk_nvme_map_prps and spdk_nvme_map_cmd were moved to nvmf/vfio-user as internal APIs as vfio-user is the only user for the above two APIs.

Added a new function spdk_nvme_ns_cmd_copy to submit a Simple Copy Command to a Namespace.

Update the spdk_nvme_generic_command_status_code structure with new status code according to the definition in NVMe 1.4 spec.

spdk_nvme_ctrlr_get_default_ctrlr_opts now sets use_cmb_sqs to false. This means that if a controller has a CMB and supports SQs in the CMB, SPDK will not use the CMB for SQs by default - the user must set use_cmb_sqs to true in the spdk_nvme_ctrlr_opts structure prior to controller attach.

Add a new function spdk_nvme_detach_poll to simplify a common use case to continue polling until all detachments complete.

Added new argument timeout_admin_us to spdk_nvme_ctrlr_register_timeout_callback so callers can specify a different timeout for admin commands vs. io commands.

An existing function spdk_nvme_detach_async was updated to add one or more detachments to an active context while it is being polled.

Rename a variable in the member cmic of the struct spdk_nvme_ctrlr_data from multi_host to multi_ctrlr. The variable means that the NVM subsystem may have two or more controllers if set to 1. However multi_host had indicated a particular use case such that the NVM subsystem is used by multiple hosts.

A new option disable_read_ana_log_page was added to struct spdk_nvme_ctrlr_opts to disable reading ANA log page. The upper layer is expected to read ANA log page instead if true. The default value is false.

New APIs, spdk_nvme_ctrlr_reset_async and spdk_nvme_ctrlr_reset_poll_async, have been added to reset a controller asynchronously.

New RPC bdev_nvme_reset_controller was added, to reset an NVMe controller.

Added spdk_nvme_ns_get_nguid function to get NGUID for the given namespace.

Added spdk_nvme_ctrlr_is_fabrics function to indicate whether a ctrlr handle is associated with a fabrics controller.


Added min_cntlid and max_cntlid to nvmf_create_subsystem to limit the controller ID range. Added spdk_nvmf_subsystem_get_min_cntlid and spdk_nvmf_subsystem_get_max_cntlid to request those values.

spdk_nvmf_request_get_buffers_multi API is removed.

Added the nvmf_set_crdt RPC for setting command retry delay times.

Expanded spdk_nvmf_poll_group_stat with current qpair count statistics.

Removed following deprecated APIs:

  • spdk_nvmf_poll_group_get_stat (function in nvmf.h),
  • spdk_nvmf_transport_poll_group_get_stat (function in nvmf.h),
  • spdk_nvmf_transport_poll_group_free_stat(function in nvmf.h),
  • spdk_nvmf_rdma_device_stat (struct in nvmf.h),
  • spdk_nvmf_transport_poll_group_stat (struct in nvmf.h),
  • poll_group_get_stat (transport op in nvmf_transport.h),
  • poll_group_free_stat (transport op in nvmf_transport.h).


New RPC bdev_rbd_register_cluster and bdev_rbd_unregister_cluster was added, it allows to create and delete the rados object cluster, then users can choose the cluster to create related rbd device.

Revised bdev_rbd_create parameter, it allows to use an optional parameter --cluster-name to create a rbd bdev with an already registered Rados Cluster Object.

New RPC bdev_rbd_get_clusters_info was added, it allows to get the info of the registered Rados Cluster names.

New optional parameter, timeout_admin_us, added to the bdev_nvme_set_options RPC.

Revised a parameter --stripe-size_kb to --stripe-size-kb of bdev_raid_create method provided in scripts/ for consistency.

An new optional parameter config_kernel_mode was added to the RPC idxd_scan_accel_engine, and this is used to enable using the kernel mode IDXD driver.

Removed deprecated parameter enable-zerocopy-send of RPC sock_impl_set_options, use enable-zerocopy-send-server or enable-zerocopy-send-client instead. Removed deprecated parameter disable-zerocopy-send of RPC sock_impl_set_options, use disable-zerocopy-send-server or disable-zerocopy-send-client instead.


Removed deprecated pkg/spdk.spec, please use rpmbuild/spdk.spec instead. See RPM documentation for more details.


Red-black tree has been used for timed pollers to provide faster insertion and deletion and for io_devices to provide faster lookup.

Removed spdk_io_channel structure from public header and moved it to thread_internal.h.


Added spdk_trace_register_description_ext function to register variable number of tracepoint arguments.

Added ability to chain multiple trace entries together to extend the size of the argument buffer.


Red-black tree macros has been added by using the macros provided by the FreeBSD operating system under the same BSD license.

Add an new macro SPDK_SIZEOF_MEMBER to get the size of a member of a struct.

spdk_crc32c_iov_update function was added to support calculating the crc32c of the iovs.

Added zipf random number generator with power law probability distribution. When applied to performance testing of block devices, it will select blocks over the full range of LBAs, but will more frequently select lower-numbered LBAs.



Two new accelerated crc32 functions spdk_accel_submit_crc32cv and spdk_accel_batch_prep_crc32cv are added in order to provide the chained accelerated CRC32 computation support.


For bdev_ocssd_create RPC, the optional parameter range was removed. Only one OCSSD bdev can be created for one OCSSD namespace.

Removed the spdk_bdev_open from bdev library API. Removed the spdk_vbdev_register and spdk_bdev_part_base_construct from bdev module API. Removed the config_text function for bdev modules to report legacy config.

Added spdk_bdev_get_max_active_zones API to display maximum number active zones of a given bdev.

Added spdk_bdev_get_max_zone_append_size API to display maximum zone append data transfer size.


Added support for zoned namespaces.


Removed the spdk_bdev_create_bs_dev_from_desc and spdk_bdev_create_bs_dev API.


Added spdk_pci_device_allow API to allow applications to add PCI addresses to the allowed list after the application has started.

Removed the pci_whitelist, pci_blacklist and master_core members of struct spdk_env_opts.

Added hotplug support based on uevent in pci_event.c. Added usage of this functionality in nvme, virtio-scsi and virtio_blk libraries. Please see the new API spdk_pci_event_listen, spdk_pci_get_event, spdk_pci_register_error_handler and spdk_pci_unregister_error_handler.


Removed the config_file, max_delay_us, pci_whitelist and pci_blacklist members of struct spdk_app_opts.


A new API spdk_idxd_device_needs_rebalance was added so that users of the library can know whether they need to rebalance the flow control for the channel that was just added/removed. This is based on how the low level library shares devices amongst channels.

The API spdk_idxd_reconfigure_chan had the num_channels removed as this is now tracked in the library. The app makes use the new API above to determine whether to rebalance or not. This applies to spdk_idxd_configure_chan as well.

The API spdk_idxd_put_channel now returns the rebalance state for the underlying device.


A security vulnerability has been identified and fixed in the SPDK iSCSI target. A TEXT PDU with no data, but CONTINUE flag set, would result in a NULL pointer dereference and crash the SPDK iSCSI target process. All users of the SPDK iSCSI target are recommended to update. All SPDK versions <= v21.01 are affected.


The net library is deprecated and will be removed in the 21.07 release.


Added a new function spdk_nvme_ctrlr_get_regs_pmrcap to get the PMR capabilities.

Added an accelerated table pointer in spdk_nvme_poll_group which can be used to provide the accelerated functions by users with hardware engine, such as crc32c accelerated function.

Added new functions spdk_nvme_ctrlr_get_pmrsz, spdk_nvme_ctrlr_enable_pmr, spdk_nvme_ctrlr_disable_pmr, spdk_nvme_ctrlr_map_pmr and spdk_nvme_ctrlr_unmap_pmr.

Added NVMe transport operations to enable, disable, map and unmap the PMR.

Added spdk_nvme_qpair_get_optimal_poll_group function and qpair_get_optimal_poll_group function pointer in spdk_nvmf_transport_ops structure in order to add the qpair to the most suitable polling group.

Added OPTPERF and namespace optimal performance fields to nvme_spec.h.

Added spdk_nvme_set_hotplug_filter API to allow applications to choose which hot-inserted SSDs should be probed. This is useful for use cases where multiple independent SPDK processes are running on one node. The filter function can then be implemented in these processes to decide which SSDs to probe based on the new SSD's PCI address.

New functions spdk_nvme_poll_group_get_stats and spdk_nvme_poll_group_free_stats were added. These functions allow to get transport statistics per NVME poll group.

Added spdk_nvme_map_cmd API to map the NVMe command with SGL cases.

Added support for vector variant of ZNS zone append commands with new API spdk_nvme_zns_zone_appendv and spdk_nvme_zns_zone_appendv_with_md.

Added spdk_nvme_zns_ns_get_max_open_zones and spdk_nvme_zns_ns_get_max_active_zones API, to display maximum number of open and active zones of the given namespace.

Added spdk_nvme_zns_ns_get_zone_size_sectors API to provide size of zone in number of sectors.

Added spdk_nvme_qpair_get_id API to display the ID of the specified qpair.


Removed the spdk_nvmf_tgt_listen and spdk_nvmf_subsystem_add_ns API.

Added new APIs:

  • spdk_nvmf_poll_group_dump_stat (function in nvmf.h).
  • poll_group_dump_stat (transport op in nvmf_transport.h).

The following APIs have been deprecated and will be removed in SPDK 21.07:

  • spdk_nvmf_poll_group_get_stat (function in nvmf.h),
  • spdk_nvmf_transport_poll_group_get_stat (function in nvmf.h),
  • spdk_nvmf_transport_poll_group_free_stat(function in nvmf.h),
  • spdk_nvmf_rdma_device_stat (struct in nvmf.h),
  • spdk_nvmf_transport_poll_group_stat (struct in nvmf.h),
  • poll_group_get_stat (transport op in nvmf_transport.h),
  • poll_group_free_stat (transport op in nvmf_transport.h).

See header files for details.

The trtype field in JSON returned by nvmf_get_stats RPC contains now the name of the transport, which is the same as the type for defined transports and more informative for a custom transport.

Added hdgst and ddgst parameters to bdev_nvme_attach_controller RPC in order change state of TCP header and data digest.

Added num_cqe parameter to nvmf_create_transport RPC to set number of completion queues (CQ) for RDMA transport. Useful when CQ resize operation is not supported, for example iWARP.


Updated OCF submodule to v20.12.2

Added bdev_ocf_set_cache_mode RPC to dynamically switch cache mode of OCF bdev.

OCF deprecation notice has removed as Huawei is picking up support for the OCF project.


Removed the spdk_opal_supported API.


For bdev_raid_create RPC, the deprecated parameter strip_size was removed.


New RPC bdev_nvme_get_transport_statistics was added, it allows to get transport statistics of nvme poll groups.

Parameter enable-zerocopy-send of RPC sock_impl_set_options is deprecated and will be removed in SPDK 21.07, use enable-zerocopy-send-server or enable-zerocopy-send-client instead. Parameter disable-zerocopy-send of RPC sock_impl_set_options is deprecated and will be removed in SPDK 21.07, use disable-zerocopy-send-server or disable-zerocopy-send-client instead.

Added used to parse the args from argparse. There are two benefit to use command parser:

  • Simplify the definition of rpc method. It will reduce the rpc method code.
  • Make the rpc call more versatile. User can add private args into rpc method.


Added support for new RPM spec, rpmbuild/spdk.spec, which can be used for packaging the SPDK. The pkg/spdk.spec is considered to be deprecated and scheduled for removal in SPDK 21.07. See RPM documentation for more details.


The type of enable_placement_id in struct spdk_sock_impl_opts is changed from bool to int. We can use RPC to configure different value of enable_placement_id. Then we can leverage SO_INCOMING_CPU to get placement_id, which aims to utilize CPU cache locality, enabled by setting enable_placement_id=2.

A new socket placement mode called PLACEMENT_MARK has been added. Some NICs allow sockets to be marked using the SO_MARK socket option as a hint for which hardware queue they should be associated with. This mode leverages that by setting the same value for all sockets within a poll group.

New parameters enable_zerocopy_send_server and enable_zerocopy_send_client were added to struct spdk_sock_impl_opts, these parameters enable or disable zero copy send for server and client sockets which are created using spdk_sock_listen and spdk_sock_listen_ext (server); spdk_sock_connect and spdk_sock_connect_ext (client) functions. Existing parameter enable_zerocopy_send enables or disables zero copy send for both server and client sockets.


A new API spdk_io_channel_get_io_device was added to get the io_device for the specified I/O channel.

Added spdk_thread_set_interrupt_mode function in order to set present spdk_thread into interrupt mode or back to poll mode. It is valid only when thread interrupt facility is enabled by spdk_interrupt_mode_enable.

Added spdk_poller_register_interrupt function to mark that the poller is capable of entering interrupt mode. Callback function will be called when the poller must transition into or out of interrupt mode.


Added the bdev_virtio_blk_set_hotplug RPC for the virtio blk pci device.



An opts_size element was added in the spdk_bdev_opts structure to solve the ABI compatibility issue between different SPDK version. And also add opts_size parameter in spdk_bdev_get_opts function. Two fields small_buf_pool_size and large_buf_pool_size were added into spdk_bdev_opts, which were used to determine the small and large buffer pool size of the whole bdev module.

A new API spdk_bdev_wait_for_examine was added to allow for checking state of examine process. Along with corresponding bdev_wait_for_examine RPC, which is now always called during spdk_bdev_subsystem_config_json making sure every bdev is ready to be used.

A new API spdk_bdev_io_get_aio_status was added for getting the status of bdev_io as Linux AIO errno. Also spdk_bdev_io_complete_aio_status function and SPDK_BDEV_IO_STATUS_AIO_ERROR were added for bdev module to complete a bdev_io with Linux AIO errno.

A new API spdk_bdev_get_module_name was added for getting block device module name. Also spdk_bdev_get_module_ctx was added to obtain a bdev module context for the block device opened by the specified descriptor.

Added max_segment_size and max_num_segments to spdk_bdev structure for bdev modules to specify splitting requirements.


An opts_size element was added in the spdk_bs_opts structure to solve the ABI compatibility issue between different SPDK version. And also add opts_size parameter in spdk_bs_opts_init function.

An opts_size element was added in the spdk_blob_opts structure to solve the ABI compatibility issue between different SPDK version. And also add opts_size parameter in spdk_blob_opts_init function.

An opts_size element was added in the spdk_blob_open_opts structure to solve the ABI compatibility issue between different SPDK version. And also add opts_size parameter in spdk_blob_open_opts_init function.


SPDK now generates pkg-config files to simplify the process of determining which libraries must be linked into an SPDK application.


Updated DPDK submodule to DPDK 20.11.

Removed --with-igb-uio-driver configure option. Since DPDK 20.11 igb_uio driver was moved to separate dpdk-kmods repository. If required, users need to refer to dpdk-kmods repository to build the driver.


The pci_whitelist, pci_blacklist and master_core members of struct spdk_env_opts have been deprecated. The new members are named pci_allowed, pci_blocked and main_core respectively.

An opts_size element was added in the spdk_app_opts structure to solve the ABI compatibility issue between different SPDK version. An opts_size parameter is added into spdk_app_opts_init function.


The pci_whitelist and pci_blacklist members of struct spdk_app_opts have been deprecated. The new members are named pci_allowed and pci_blocked respectively.

The --pci-blacklist command line option has been deprecated, replaced with --pci-blocked.

The --pci-whitelist/-W command line options have been deprecated, replaced with --pci-allowed/-A.

Added new experimental dynamic scheduler that rebalances idle threads, adjusts CPU frequency using dpdk_governor and turns idle reactor cores to interrupt mode. Please see scheduler documentation for details.


The PCI BDF whitelist option has been removed from the ioat_scan_accel_engine RPC. IOAT PCI functions can still be allowed or denied using SPDK application command line options.


Updated ISA-L submodule to v2.30.0.


A new API spdk_jsonrpc_send_bool_response was added to allow sending response for writing json bool results into one function. Update API bdev_nvme_set_options and add a keep_alive_timeout_ms parameter. Now you can specify the keep_alive_timeout before creating NVMe bdev.


Change the return type of function spdk_nbd_stop from void to int. And update the spdk_nbd_fini with two parameters to make its behavior from sync to async.


Directives support was added to the NVMe driver.

Two async APIs spdk_nvme_ctrlr_cmd_directive_receive and spdk_nvme_ctrlr_cmd_directive_send are added for Directive Send and Directive Receive command, respectively.

Added a new function spdk_nvme_ctrlr_reset_subsystem to perform a NVMe subsystem reset. Note: The NVMe-oF target does not support the subsystem reset yet.

Add a new function spdk_nvme_bytes_to_numd to transfer bytes to number of dwords.

Added a new custom transport SPDK_NVME_TRANSPORT_VFIOUSER to enable NVMe driver running with NVMe over vfio-user target.

Added the vfio-user custom transport implementation in NVMe driver which can connect to NVMe over vfio-user target via vfio-user transport.

Added a new function spdk_nvme_ctrlr_set_remove_cb to remove or override remove_cb and remove_ctx specified when the controller was probed.

Added support for ZNS zone append command with new API spdk_nvme_zns_zone_append and spdk_nvme_zns_zone_append_with_md.


nvmf_fc_lld_fini now takes callback and hence updating FC Broadcom LLD driver to the latest is required.

FC transport supported primary tagging and VMID.

Broadcom FC LLD driver and SPDK NVMe-oF FC transport consolidated one LLD API, nvmf_fc_init_poller_queues into another LLD API nvmf_fc_init_q. Hence updating Broadcom FC LLD driver to the latest is required.

The functions destroy and qpair_fini in the transport interface now accept a cb_fn and cb_arg to call upon completion, and their execution can be asynchronous.

The SPDK NVMe-oF target now supports async event notification for discovery log changes. This allows the initiator to create persistent connection to discovery controller and be notified of any discovery log changes.

An opts_size element was added in the spdk_nvmf_transport_opts structure to solve the ABI compatibility issue between different SPDK version. And also add opts_size parameter in spdk_nvmf_transport_opts_init function.

Added a new custom vfio-user transport implementation in NVMe-oF which can provide emulated NVMe devices to QEMU and SPDK NVMe driver.

Added new API spdk_nvmf_tgt_listen_ext that uses spdk_nvmf_listen_opts to allow passing generic options to specific transport. This functionality replaces one provided with nvmf_subsystem_set_options. Also removed nvmf_subsystem_set_options RPC that allowed transport specific options within subsystem.

The trsvcid in nvmf_subsystem_add_listener RPC is now optional.

Pausing a subsystem now only pauses all admin queues. This allows for the management of hosts and listeners, plus the addition of namespaces without a full subsystem pause. Additionally, the target now allows for pausing individual namespaces within a subsystem. To remove a namespace from a subsystem, only the specific namespace must be paused. I/O will continue to other namespaces while these operations execute.


An new optional parameter wait was added to the RPC iscsi_create_portal_group, and an new RPC iscsi_start_portal_group was added. They will be used not to start listening on portals for a portal group until all associated target nodes are created at startup, otherwise some iSCSI initiators may fail to re-login when SPDK iSCSI target application restarts.

Two optional parameter --small-buf-pool-size and --large-buf-pool-size were added into bdev_set_options function.


Added optional packed_ring_recovery parameter to vhost_create_blk_controller RPC enabling packed ring live recovery.



New APIs spdk_accel_batch_cancel and spdk_idxd_batch_cancel were added to allow cancelling a batch sequence.


A new spdk_bdev_part_base_construct_ext function has been added and the spdk_bdev_part_base_construct has been deprecated. The spdk_bdev_part_base_construct_ext function takes bdev name as an argument instead of bdev structure to avoid a race condition that can happen when the bdev is being removed between a call to get its structure based on a name and actually opening it.

Removed spdk_bdev_config_text function for bdev modules to report legacy config.


A new spdk_bdev_create_bs_dev_ext function has been added and spdk_bdev_create_bs_dev_from_desc function has been deprecated.


Updated DPDK submodule to DPDK 20.08.


A new API spdk_mem_get_fd_and_offset was added to get file descriptor and offset for a given virtual address.


Removed spdk_subsystem_config callback for submodules as part of legacy config removal.

Removed spdk_app_get_running_config function that printed configuration in legacy format, and removed usr1_handler from struct spdk_app_opts callback that was used to call it.

Added SPDK thread scheduler framework which is used to rebalance load among CPU cores. The scheduler implementation is pluggable and two schedulers are added first, static scheduler and gscheduler scheduler.

static scheduler is used by default and does not reschedule threads and keeps the initial assignments.

CPU frequency governor framework and implementation are also added. dpdk_governor is the first implementation and is based on rte_power library of DPDK. gscheduler scheduler utilizes the CPU frequency governor.

Scheduler and governor frameworks are experimental features.


Bdev fio_plugin no longer supports legacy configuration files. Options spdk_conf and spdk_json_conf have to point to valid JSON configuration.


Removed option to disable GPT probing via legacy configuration. Please use generic bdev functionality to replicate the behavior. See bdev_set_options --disable-auto-examine and bdev_examine RPC.


Updated intel-ipsec-mb submodule to v0.54


Updated ISA-L submodule to v2.29.0.


The iSCSI target supports iSCSI login redirection feature to achieve fault tolerance and load balancing particularly in scale out iSCSI target system, which runs multiple SPDK iSCSI targets.


A new API spdk_json_decode_object_relaxed was added to allow parsing json values even if decoder for a given key is not found.

A new API spdk_json_free_object was added to free memory allocated by spdk_json_decode_object.


A log flag structure, spdk_log_register_flag, spdk_log_get_first_flag, spdk_log_get_next_flag and macro SPDK_LOG_REGISTER_COMPONENT, have been added which enable registering and interacting with log flags. Added SPDK_INFOLOG, SPDK_DEBUGLOG and SPDK_LOGDUMP macros to display logs for specified log flag.

The log flags in the event framework -L and several SPDK applications has been enabled on release builds of SPDK. On debug builds this option will additionally set log print level to SPDK_LOG_DEBUG.

A new API spdk_log_enable_timestamps and new RPC log_enable_timestamps was added to toggle log timestamps.


The contents of the log_rpc library have been moved to the event library. The log_rpc library now no longer exists.

The contents of the app_rpc library have been moved to the event library. The app_rpc library now no longer exists.

The contents of the bdev_rpc library have been moved to the bdev library. The app_rpc library now no longer exists.

The bdevperf application now disables the zcopy API by default. Prior to this change, bdevperf enabled using the zcopy API by default which caused a performance impact of up to 25% on bdevs that don't natively support zcopy because the API emulates zero-copy by allocating a buffer. The bdevperf -x param was renamed to -Z and the default value changed to false. For bdevs that support zcopy, use the -Z flag to enable using zcopy API.


Net framework intended for use by user-space TCP stacks was removed.


Zoned Namespace Command Set support has been added to NVMe driver, see nvme_zns.h for details.

New APIs, spdk_nvme_detach_async and spdk_nvme_detach_poll_async, have been added to detach multiple controllers in parallel to mitigate lengthy shutdown notification of a few NVMe SSDs.

New APIs, spdk_nvme_ns_get_ana_group_id and spdk_nvme_ns_get_ana_state, have been added to get ANA group ID and ANA state of the given namespace, respectively.

If no specific command set is requested (by setting the command_set member in the spdk_nvme_ctrlr_opts structure), SPDK will automatically select the most appropriate command set based on what the controller supports.


A new API spdk_nvmf_subsystem_add_ns_ext has been added and the API spdk_nvmf_subsystem_add_ns has been deprecated.

The NVMe-oF target now supports Asymmetric Namespace Access (ANA) Reporting to provide multipath to NVMe-oF initiator.

Add no_wr_batching parameter to spdk_nvmf_transport_opts struct to disable Work Requests batching in RDMA transport.

NVMf Target transports can now parse any additional JSON params in the nvmf_create_transport RPC through the JSON context provided via spdk_nvmf_target_opts->transport_specific.

A new RPC nvmf_subsystem_set_options was added to allow transport specific options within subsystem.

A new API spdk_nvmf_transport_stop_listen_async was added to stop accepting new connections at the provided address. nvmf_subsystem_remove_listener RPC now uses this function.

A new API spdk_nvmf_subsystem_disconnect_host was added to disconnect all connections originating from the provided hostnqn. nvmf_subsystem_remove_host RPC now uses this function.


Updated OCF submodule to v20.03.1


New optional parameters, enable_placement_id and enable_quickack were added to the sock_impl_set_options RPC.

A new RPC bdev_examine_bdev was added to allow users to examine a bdev explicitly. It can be used only if bdev_auto_examine is set to false by the RPC bdev_set_options.

New optional parameters no_wr_batching and control_msg_num were added to the RPC 'nvmf_create_transport'.

New RPCs, iscsi_target_node_set_redirect and iscsi_target_node_request_logout, have been added, and a new optional parameter private has been added to the RPC iscsi_create_portal_group to support iSCSI login redirection feature.

A new optional parameter ana_reporting was added to the RPC nvmf_create_subsystem, and a new RPC nvmf_subsystem_listener_set_ana_state was added for ANA reporting.

New RPCs, nvmf_subsystem_get_listeners and nvmf_subsystem_get_qpairs, were added to retrieve configuration of the NVMe-oF subsystem.


Two new APIs have been added spdk_scsi_dev_construct_ext and spdk_scsi_dev_add_lun_ext that allow the upper layer(e.g. vhost-scsi) to receive the notification when the scsi bdev has been resized.

The spdk_scsi_dev_construct and spdk_scsi_dev_add_lun eventually may be deprecated and removed.


The enable_placement_id field was added in the struct spdk_sock_impl_opts to make the placement_id feature configurable by users. The default setting is not enabled.

The enable_quick_ack field was added in the struct spdk_sock_impl_opts to enable or disable quick ack for the POSIX sock module. The default setting is not enabled.


fd_group is applied to support interrupt mode. New APIs were added to support an experimental interrupt mode. This allows modules or libraries to selectively register file descriptors that the spdk_thread can wait on, as an alternative to polling. In v20.10, this functionality is enabled in a very small subset of SPDK libraries and modules.


A new utility named fd_group was add. It is now implemented by epoll on Linux platform. It can be used by spdk_thread and reactor to implement interrupt mode.

Added spdk_bit_pool utility, see bit_pool.h for details.


SPDK has switched to DPDK's rte_vhost library since 19.07 release, removed the internal rte_vhost library which is used for DPDK older than 19.05, removed the experimental vhost nvme target which depends on the internal rte_vhost library.


Removed socket abstraction for VPP.

v20.07: SPDK CSI driver, new accel_fw commands, I/O abort support

spdk_json_free_object() was added to free memory allocated by spdk_json_decode_object().


A new API was added spdk_accel_get_capabilities that allows applications to query the capabilities of the currently enabled accel engine back-end.

A new capability, CRC-32C, was added via spdk_accel_submit_crc32c.

The software accel engine implementation has added support for CRC-32C.

A new capability, compare, was added via spdk_accel_submit_compare.

The software accel engine implementation has added support for compare.

Several APIs were added to accel_engine.h to support batched submission of operations.

Several APIs were added to accel_engine.h to support dualcast operations.


The accel_fw was updated to no longer require the app to allocate an accel_task on its behalf. All public APIs now take a callback arg as the parameter that used to be the accel_task.

The accel_fw API spdk_accel_task_size was removed as it is no longer required.

The accel_fw was updated to support compare, dualcast, crc32c.

The accel_fw introduced batching support for all commands in all plug-ins. See docs for detailed information.


A new API spdk_bdev_abort has been added to submit abort requests to abort all I/Os whose callback context match to the bdev on the given channel.


The fio plugins now compile to build/fio and are named spdk_bdev and spdk_nvme. Existing fio configuration files will need to be updated.


Updated DPDK submodule to DPDK 20.05.


Several new APIs have been added to provide greater flexibility in registering and accessing polled mode PCI drivers. See env.h for more details.


The idxd library and plug-in module for the accel_fw were updated to support all accel_fw commands as well as batching. Batching is supported both through the library and the plug-in module.

IDXD engine support for CRC-32C has been added.


A new API spdk_ioat_get_max_descriptors was added.


An opts_sizeelement was added in the spdk_nvme_ctrlr_opts structure to solve the ABI compatibility issue between different SPDK version.

A new API spdk_nvme_ctrlr_cmd_abort_ext has been added to abort previously submitted commands whose callback argument match.

Convenience functions, spdk_nvme_print_command and spdk_nvme-print_completion were added to the public API.

A new function, spdk_nvmf_cuse_update_namespaces, updates the cuse representation of an NVMe controller.

A new function qpair_iterate_requests has been added to the nvme transport interface. ALl implementations of the transport interface will have to implement that function.


The NVMe-oF target no longer supports connecting scheduling configuration and instead always uses what was previously called "transport" scheduling.

spdk_nvmf_tgt_accept no longer exists. The accept process now occurs automatically after the creation of an nvmf target and queue pairs are assigned to poll groups by the underlying transport. Further, spdk_nvmf_transport_ops has changed such that the accept function pointer no longer takes a function pointer as an argument. Instead, transports should call spdk_nvmf_tgt_new_qpair whenever they previously would have called that callback.

The NVMe-oF target now supports aborting any submitted NVM or Admin command. Previously, the NVMe-oF target could abort only Asynchronous Event Request commands.


A new rdma library has been added. It is an abstraction layer over different RDMA providers. Two providers are available - verbs (used by default when RDMA is enabled or enabled explicitly using –with-rdma=verbs) and mlx5 Direct Verbs aka DV (enabled by –with-rdma=mlx5_dv). Using mlx5_dv requires libmlx5 installed on the system.


Parameter -p or --max-qpairs-per-ctrlr of nvmf_create_transport RPC command accepted by the script is deprecated, new parameter -m or --max-io-qpairs-per-ctrlr was added.

Added sock_impl_get_options and sock_impl_set_options RPC methods.

Command line parameters -r and --rpc-socket will longer accept TCP ports. RPC server must now be started on a Unix domain socket. Exposing RPC on the network, as well as providing proper authentication (if needed) is now a responsibility of the user.

The bdev_set_options RPC has a new option, bdev_auto_examine to control the auto examine function of bdev modules.

New RPCs sock_impl_get_options and sock_impl_set_options been added to expose new socket features. See sock section for more details.


Added spdk_sock_impl_get_opts and spdk_sock_impl_set_opts functions to set/get socket layer configuration options. Options can be set independently for each implementation.

Added recv_buf_size and 'send_buf_size' socket layer options. They are used only in posix implementation.

Added uring based socket implementation, the code is located in module/sock/uring. This feature is only available in Linux which requires kernel version is greater than 5.4.3. Currently, our CI pool added the uring based socket tests for iSCSI target and also the tests for SPDK NVMe-oF tcp transport.

Added enable_recv_pipe socket layer option to allow disabling of double buffering on receive. New option is used only in posix implementation.

Added enable_zerocopy_send socket layer option to allow disabling of zero copy flow on send. New option is used only in posix implementation.


Some previously exposed CRC32 functions have been removed from the public API - spdk_crc32_update, spdk_crc32_table_init, and the spdk_crc32_table struct.


The function spdk_vhost_blk_get_dev has been removed.

v20.04: SPDK Top, IDXD, NVMe qpair groups

IDXD engine support for compare has been added.


Legacy INI style configuration for SPDK applications has been deprecated and will be removed in future release. Please switch to JSON-RPC configuration files and/or RPC driven run-time configuration.


The copy engine library, modules and public APIs have been renamed. Use of the word copy has been replaced with the word accel short for accelerator in preparation for adding new capabilities in the future. Additionally, APIs for what was previously called the memcpy engine have been renamed to identify the engine as a software accelerator.


Support for AES_XTS was added for the QAT polled mode driver (pmd). The create RPC bdev_crypto_create has 2 new optional parameters: cipher and key2. Cipher can be either AES_CBC (default) or AES_XTS. AES_XTS is only valid when using the QAT polled mode driver. The key2 parameter is the second key required for AES_XTS.


Reactors now accumulate CPU stats and they are retrieved by the RPC framework_get_reactors.


IDXD support was added in the form of a low level library that can directly utilize the IDXD offload engine as well as an accel plug-in module allowing for use with the generic accel framework API. IDXD is the first in a family of offload engines that share the same interface, specifically DSA is added here. More info can be found here:

Much of the implementation models IOAT, however the low level interfaces are very different. The RPC to enable IDXD requires a configuration number as well. The code includes two pre-defined configurations of IDXD groups/work queues/engines. A future version will provide an interface to allow for setting of individual configuration parameters.

IDXD is not yet available so this feature should be considered experimental. It will be built up with additional documentation as an ongoing activity.


The iSCSI target now creates a lightweight thread per poll group instead of assuming a pool of lightweight threads already exist at start up time. A poll group is a collection of unrelated iSCSI connections. Each poll group is only accessed from the associated lightweight thread.


Several changes have been made to the spdk_ftl_conf, spdk_ftl_dev_init_ops, and spdk_ftl_attrs structs. Please see include/spdk/ftl.h for more details.


The --json-ignore-init-errors command line parameter has been added to ignore initialization errors on JSON config load.

The public header file io_channel.h has been removed. Please use thread.h which has the exact same API.


Exported internal nvme_ctrlr_cmd_security_receive/send() APIs as public APIs with "the spdk_" prefix.

Added priority field in spdk_nvme_transport_id, this field is used to specify the priority of the NVMe-oF connection, and currently it is used for NVMe-oF tcp connection.

A new poll group API has been added to allow for pooling of nvme qpairs across a single entity which can be polled for completions. This new API consists of the spdk_nvme_poll_group family of functions. As a result of this new API, all NVMe transports are expected to implement several poll group related functions.

A new flag, create_only, has been added to the spdk_nvme_io_qpair_opts structure. This flag allows a user to call spdk_nvme_ctrlr_get_default_io_qpair without also connecting the qpair within the context of that call.

As a result of the create_only flag, two new API functions, spdk_nvme_ctrlr_connect_io_qpair and spdk_nvme_ctrlr_disconnect_io_qpair, have been added to facilitate connecting newly created qpairs (for example, after they have been added to a poll group) and disconnecting qpairs without destroying them (for example to disconnect a qpair before migrating it to a new poll group and reconnecting it).

The functions spdk_nvme_ctrlr_alloc_cmb_io_buffer and spdk_nvme_ctrlr_free_cmb_io_buffer have been changed to spdk_nvme_ctrlr_map_cmb and spdk_nvme_ctrlr_unmap_cmb respectively.

An additional function, spdk_nvme_ctrlr_reserve_cmb, has been added to facilitate reserving the entire size of the controller memory buffer for data transfer.


spdk_nvme_cuse_get_ctrlr_name now takes two additional parameters, char *name which stores the pointer to the controller name, and size_t *size which stores the length of the name. The return type has also been changed from char * to int.

spdk_nvme_cuse_get_ns_name now takes two additional parameters, char *name which stores the pointer to the namespace name, and size_t *size which stores the length of the name. The return type has also been changed from char * to int.


Several public OPAL structure definitions have been changed since the last release.


spdk_nvmf_poll_group_destroy() is now asynchronous and accepts a completion callback.

The NVMe-oF target now creates a lightweight thread per poll group instead of assuming a pool of lightweight threads already exist at start up time. A poll group is a collection of unrelated NVMe-oF connections. Each poll group is only accessed from the associated lightweight thread.

A new struct, spdk_nvmf_subsystem_listener, has been added to encapsulate the subsystem specific nature of a listener object.

spdk_nvmf_tgt_listen no longer accepts a callback function or argument. It also returns an int to indicate the status of the listen call.

The execution of spdk_nvme_poll_group_destroy is now asynchronous and the function accepts a cb_fn and cb_arg to call upon completion.

The execution of spdk_nvmf_subsystem_add_listener is now asynchronous and the function accepts a cb_fn and cb_arg to call upon completion.

The nvmf_transport.h header has been made public to allow custom NVMe-oF transports to integrate with NVMe-oF libraries without using internal APIs.


Updated the OCF submodule to OCF v20.03

New version of OCF comes with API changes and bug fixes


A new RPC thread_set_cpumask has been added to set the cpumask of the thread to the specified value.

A new RPC thread_get_pollers has been added to retrieve pollers from SPDK threads.

A new RPC thread_get_io_channels has been added to retrieve I/O channels from SPDK threads.

A new RPC bdev_rbd_resize has been added to resize Ceph RBD bdevs.


The spdk_sock_set_priority function has been removed since the feature to set the sock priority will be contained in two new functions, i.e., spdk_sock_listen_ext and spdk_sock_connect_ext. Users may now specify the priority of the socket in the opts that they want to use.


A new application, spdk_top, has been added which allows users to monitor resource consumption by a running SPDK application. More information on this application can be found in app/spdk_top/README.


A new function spdk_thread_lib_init_ext has been added, and the function spdk_thread_lib_init has been deprecated. The user of spdk_thread_lib_init_ext is expected to implement both functions spdk_thread_op_fn and spdk_thread_op_supported_fn. spdk_thread_op_supported_fn is called to check whether the SPDK thread operation is supported. spdk_thread_op_fn is called to execute the SPDK thread operation. Current SPDK operation types are SPDK_THREAD_OP_NEW and SPDK_THREAD_OP_RESCHED. The operation SPDK_THREAD_OP_NEW is called each time a new thread is created. The operation SPDK_THREAD_OP_RESCHED is called when SPDK thread needs to be rescheduled.

A unique ID has been added for each created SPDK thread, it is retrieved by a new function spdk_thread_get_id, and the SPDK thread which has the specific ID is got by a new function spdk_thread_get_by_id.

A new function spdk_thread_cpumask has been added to set the current thread's cpumask to the specified value. The function requires the operation SPDK_THREAD_OP_RESCHED is supported.

A new function spdk_poller_register_named has been added to set arbitrary name to the created poller. If NULL, the name is set to the pointer of the poller function.

The function spdk_thread_poll now measures run time per call correctly on multiple SPDK threads configuration, and a new function spdk_thread_get_last_tsc has been added to use together.

Voluntary termination of SPDK thread has been supported by refining the functions spdk_thread_exit and spdk_thread_poll.


New functions spdk_sn32_lt and spdk_sn32_gt have been added. They compare two sequence numbers based on serial number arithmetic.


Poll groups per session have been replaced by SPDK threads per vhost controller.


A new function, spdk_vmd_fini, has been added. It releases all resources acquired by the VMD library through the spdk_vmd_init call.

v20.01: Optimized thin provisioning, FTL bdev, VMD hot plug, FUSED support


A new function, spdk_bdev_set_timeout, has been added to set per descriptor I/O timeouts.

A new class of functions spdk_bdev_compare*, have been added to allow native bdev support of block comparisons and compare-and-write.

A new class of bdev events, SPDK_BDEV_EVENT_MEDIA_MANAGEMENT, has been added to allow bdevs which expose raw media to alert all I/O channels of pending media management events.

A new API was added spdk_bdev_io_get_aux_buf allowing the caller to request an auxiliary buffer for its own private use. The API is used in the same manner that spdk_bdev_io_get_buf is used and the length of the buffer is always the same as the bdev_io primary buffer. 'spdk_bdev_io_put_aux_buf' frees the allocated auxiliary buffer.


Added boolean return value for function spdk_fs_set_cache_size to indicate its operation result.

Added blobfs_set_cache_size RPC method to set cache size for blobstore filesystem.


Added new use_extent_table option to spdk_blob_opts for creating blobs with Extent Table descriptor. Using this metadata format, dramatically decreases number of writes required to persist each cluster allocation for thin provisioned blobs. Extent Table descriptor is enabled by default. See the Blobstore Programmer's Guide for more details.


Updated DPDK submodule to DPDK 19.11.


spdk_env_dpdk_post_init now takes a boolean, legacy_mem, as an argument.

A new function, spdk_env_dpdk_dump_mem_stats, prints information about the memory consumed by DPDK to a file specified by the user. A new utility, scripts/, wraps this function and prints the output in an easy to read way.


The functions spdk_reactor_enable_framework_monitor_context_switch() and spdk_reactor_framework_monitor_context_switch_enabled() have been changed to spdk_framework_enable_context_switch_monitor() and spdk_framework_context_switch_monitor_enabled(), respectively.


All NVMe dependencies were removed from ftl library. From now ftl library is using bdev_zone API. bdev_ftl becomes virtual bdev.

ctrlr and trid fields in spdk_ftl_dev_init_opts structure were replaced by base_bdev_desc.

bdev_ftl_create RPC method trtype and traddr parameters were replaced by base_bdev parameter.

spdk_ftl_module_init and spdk_ftl_module_fini functions were removed.

spdk_ftl_punit_range and ftl_module_init_opts structures were removed.


Updated ISA-L submodule to commit f3993f5c0b6911 which includes implementation and optimization for aarch64.

Enabled ISA-L on aarch64 by default in addition to x86.


delayed_pcie_doorbell parameter in spdk_nvme_io_qpair_opts was renamed to delay_cmd_submit to allow reuse in other transports.

Added RDMA WR batching to NVMf RDMA initiator. Send and receive WRs are chained together and posted with a single call to ibv_post_send(receive) in the next call to qpair completion processing function. Batching is controlled by 'delay_cmd_submit' qpair option.

The NVMe-oF initiator now supports plugging out of tree NVMe-oF transports. In order to facilitate this feature, several small API changes have been made:

The spdk_nvme_transport_id struct now contains a trstring member used to identify the transport. A new function, spdk_nvme_transport_available_by_name, has been added. A function table, spdk_nvme_transport_ops, and macro, SPDK_NVME_TRANSPORT_REGISTER, have been added which enable registering out of tree transports.

A new function, spdk_nvme_ns_supports_compare, allows a user to check whether a given namespace supports the compare operation.

A new family of functions, spdk_nvme_ns_compare*, give the user access to submitting compare commands to NVMe namespaces.

A new function, spdk_nvme_ctrlr_cmd_get_log_page_ext, gives users more granular control over the command dwords sent in log page requests.


Add SockPriority option in [Transport] section, this can be used for NVMe-oF target on TCP transport to set sock priority for the incoming TCP connections.

The NVMe-oF target now supports plugging out of tree NVMe-oF transports. In order to facilitate this feature, several small API changes have been made:

The spdk_nvme_transport_id struct now contains a trstring member used to identify the transport. spdk_nvmf_tgt_get_transport, spdk_nvmf_transport_opts_init, and spdk_nvmf_transport_create all have been modified to take a string. A function table, spdk_nvmf_transport_ops, and macro, SPDK_NVMF_TRANSPORT_REGISTER, have been added which enable registering out of tree transports.

Add spdk_nvmf_tgt_stop_listen() that can be used to stop listening for incoming connections for specified target and trid. Listener is not stopped implicitly upon destruction of a subsystem any more.

A custom NVMe admin command handler has been added which allows the user to use the real drive attributes from one of the target NVMe drives when reporting drive attributes to the initiator. This handler can be enabled via the nvmf_set_config RPC. Note: In a future version of SPDK, this handler will be enabled by default.

The SPDK target and initiator both now include compare-and-write functionality with one caveat. If using the RDMA transport, the target expects the initiator to send both the compare command and write command either with, or without inline data. The SPDK initiator currently respects this requirement, but this note is included as a flag for other initiators attempting compatibility with this version of SPDK.

The spdk_nvme_ctrlr_opts struct has been extended with new field transport_ack_timeout which allows to configure transport ACK timeout. Applicable for RDMA transport only.


A new RPC, bdev_zone_block_create, enables creating an emulated zoned bdev on top of a standard block device.

A new RPC, bdev_ocssd_create, enables creating an emulated zoned bdev on top of an Open Channel SSD.

A new RPC, blobfs_set_cache_size, enables managing blobfs cache size.

A new RPC, env_dpdk_get_mem_stats, has been added to facilitate reading DPDK related memory consumption stats. Please see the env_dpdk section above for more details.

A new RPC, framework_get_reactors, has been added to retrieve a list of all reactors.

bdev_ftl_create now takes a base_bdev argument in lieu of trtype, traddr, and punits.

bdev_nvme_set_options now allows users to disable I/O submission batching with the -d flag

bdev_nvme_cuse_register now accepts a name parameter.

bdev_uring_create now takes arguments for bdev_name and block_size

nvmf_set_config now takes an argument to enable passthru of identify commands to base NVMe devices. Please see the nvmf section above for more details.


spdk_scsi_lun_get_dif_ctx now takes an additional argument of type spdk_scsi_task.


Added spdk_sock_writev_async for performing asynchronous writes to sockets. This call will never return EAGAIN, instead queueing internally until the data has all been sent. This can simplify many code flows that create pollers to continue attempting to flush writes on sockets.

Added impl_name parameter in spdk_sock_listen and spdk_sock_connect functions. Users may now specify the sock layer implementation they'd prefer to use. Valid implementations are currently "vpp" and "posix" and NULL, where NULL results in the previous behavior of the functions.


spdk_thread_send_msg now returns int indicating if the message was successfully sent.

A new function spdk_thread_send_critical_msg, has been added to support sending a single message from a context that may be interrupted, e.g. a signal handler.

Two new functions, spdk_poller_pause, and spdk_poller_resume, have been added to give greater control of pollers to the application owner.


spdk_pipe, a new utility for buffering data from sockets or files for parsing has been added. The public API is available at include/spdk/pipe.h.


Added spdk_bdev_io_get_nvme_fused_status function for translating bdev_io status to NVMe status code for fused compare-and-write operation.

Added spdk_bdev_get_acwu function for getting block device atomic compare and write unit size.

v19.10: Zoned bdev API, Opal bdev, NVMe character devices


Many of SPDK's RPCs were renamed to be more consistent and intuitive in this release. The old names will continue to function, but will display a deprecation warning.

Added optional parameters '–arbitration-burst' and '–low/medium/high-priority-weight' to 'bdev_nvme_set_options' RPC method.

Added optional parameter '–md-size' to 'construct_null_bdev' RPC method.

Added optional parameters '–dif-type' and '–dif-is-head-of-md' to 'construct_null_bdev' RPC method.

Added blobfs_detect RPC method to detect whether a blobfs exists on given bdev.

Added blobfs_create RPC method to build blobfs on given bdev.

Added blobfs_mount RPC method to mount blobfs on given bdev to a host path by FUSE. Then on the host path, user can directly do some file operations which will be mapped to blobfs.


Added new parameter cdw0 to spdk_bdev_io_complete_nvme_status() and spdk_bdev_io_get_nvme_status() that allows setting/getting the NVMe completion queue DW0 entry. This allows vendor specific IO commands to return command specific completion info back to the initiator.

Added spdk_bdev_get_write_unit_size() function for retrieving required number of logical blocks for write operation.

New zone-related fields were added to the result of the get_bdevs RPC call:

  • zoned: indicates whether the device is zoned or a regular block device
  • zone_size: number of blocks in a single zone
  • max_open_zones: maximum number of open zones
  • optimal_open_zones: optimal number of open zones

The zoned field is a boolean and is always present, while the rest is only available for zoned bdevs.

A new spdk_bdev_open_ext function has been added and spdk_bdev_open function has been deprecated. The new open function introduces requirement to provide callback function that will be called by asynchronous event such as bdev removal. spdk_bdev_open_ext function takes bdev name as an argument instead of bdev structure to avoid a race condition that can happen when the bdev is being removed between a call to get its structure based on a name and actually opening it.

New 'resize' event has been added to notify about change of block count property of block device. Event is delivered only if block device was opened with spdk_bdev_open_ext function.

bdev zone

Added new public header for zoned bdev. Zoned bdev is an extension of the bdev interface.

spdk_bdev_get_zone_size(), spdk_bdev_get_max_open_zones(), spdk_bdev_get_optimal_open_zones() APIs were added for retrieving zoned device information. spdk_bdev_get_zone_info() API was added for retrieving information about zones in zoned device. Added spdk_bdev_zone_management() API for changing zone state. spdk_bdev_zone_append() and spdk_bdev_zone_append_with_md() APIs were added for appending data to a zone. Added spdk_bdev_io_get_append location() function for retrieving append location for I/O. Added spdk_bdev_is_zoned() function for checking if bdev supports zoned namespace semantics.

bdev opal

EXPERIMENTAL: A new opal bdev has been added to support management of NVMe self-encrypting drives through the Opal specification. Users can create opal bdevs from an NVMe namespace bdev, if the controller containing that namespace supports Opal. Currently this is only supported for namespace ID=1. The following RPCs have been added to support Opal: bdev_nvme_opal_init, bdev_nvme_opal_revert, bdev_opal_create, bdev_opal_delete, bdev_opal_get_info, bdev_opal_new_user, bdev_opal_set_lock_state. It does not yet support recreating the opal bdevs after application restart. This bdev module should be considered very experimental, and the RPCs may change significantly in future releases.

delay bdev

The bdev_delay_update_latency has been added to allow users to update a latency value for a given delay bdev.

compress bdev

A new RPC bdev_compress_get_orphans has been added to list compress bdevs that were not loaded due to a missing pm metadata file. In this state they can only be deleted.

null bdev

Metadata support has been added to Null bdev module.

Protection information support has been added to Null bdev module.


Added no_shn_notification to NVMe controller initialization options, users can enable it for NVMe controllers. When the option is enabled, the controller will not do the shutdown process and just disable the controller, users can start their application later again to initialize the controller to the ready state.

A controller flag SPDK_NVME_CTRLR_WRR_SUPPORTED was added to indicate the controller can support weighted round robin arbitration feature with submission queue.

Added arbitration_burst option for arbitration feature, and added three low/medium/high_priority_weight options for weighted round robin arbitration.

Added spdk_nvme_ns_cmd_write_uncorrectable.

Added new error handling and reporting functionality. This includes several new API functions to facilitate applications recovering when a qpair or controller fails.

spdk_nvme_ctrlr_reconnect_io_qpair - Reconnects a failed I/O qpair. spdk_nvme_ctrlr_set_trid - Sets the trid of an existing controller. Can be used to change the trid for failover cases. spdk_nvme_ctrlr_is_failed - Returns the failed state of a controller. spdk_nvme_ctrlr_fail - Forces a controller into a failed state.

Modified the return behavior of several API functions to better indicate to applications when a qpair is failed. This list of functions includes:

spdk_nvme_qpair_process_completions spdk_nvme_ns_cmd_* spdk_nvme_ctrlr_process_admin_completions spdk_nvme_ctrlr_cmd_*

These functions now return -ENXIO when the qpair or controller on which they operate is failed.

EXPERIMENTAL: Added NVMe character device support to allow to create NVMe device nodes in Linux kernel for controller as well as for namespace and process ioctl requests as usual from linux environment.


The spdk_nvmf_tgt_create function now accepts an object of type spdk_nvmf_target_opts as its only parameter. This new structure contains the max_subsystems parameter previously passed into that function.

A new public API function spdk_nvmf_get_tgt has been added which allows users to retrieve a pointer to an spdk_nvmf_tgt object by supplying its name. In the special case where an RPC or application only creates a single target, this function can accept a null name parameter and will return the only available target.

The majority of the NVMe-oF RPCs now accept an optional tgt_name parameter. This will allow those RPCs to work with applications that create more than one target.

Three new NVMe-oF RPCs have been added nvmf_create_target, nvmf_delete_target, and nvmf_get_targets. These new RPCs provide a basic interface for managing multiple target objects. In SPDK the target object defines a unique discovery service. As of this release, these RPCs are not intended to be used with the in-tree SPDK target applications, spdk_tgt and nvmf_tgt, which use a single, global target structure. As such, they are not included in scripts/

Three new header functions have also been added to help deal with multiple targets. spdk_nvmf_tgt_get_name takes a target pointer as an argument and returns its human readable name. spdk_nvmf_get_first_target takes no arguments and returns the first target in the global list. spdk_nvmf_get_next_tgt takes a target pointer as an argument and returns the next one in the global list.

The spdk_nvmf_tgt_accept takes additional argument allowing to pass arbitrary context information to the new_qpair callback. This will simplify the code when having multiple nvmf targets or when retrieving the context information from globals is not suitable.


A new spdk_bdev_create_bs_dev_from_desc function has been added and spdk_bdev_create_bs_dev function has been deprecated. The new create function can cowork with spdk_bdev_open_ext function, which provides callback function that will be called by asynchronous event such as bdev removal.


A new blobfs module bdev has been added to simplify the operations of blobfs on bdev.

Function spdk_blobfs_bdev_detect is added to detect whether blobfs exists on the given block device.

Function spdk_blobfs_bdev_create is added to create a blobfs on the given block device.

Function spdk_blobfs_bdev_mount is added to mount a blobfs on the given block device to a host path by FUSE. Then, a new thread is created dedicatedly for one mountpoint to handle FUSE request by blobfs API.


Option to build FUSE components into blobfs_bdev module for mounting a blobfs filesystem. It requires the installation of libfuse3. By default, it is disabled. And it will be enabled if run ./configure with --with-fuse option.


Portals may no longer be associated with a cpumask. The scheduling of connections is moving to a more dynamic model.

An new RPC iscsi_portal_group_set_auth has been added to set CHAP authentication for discovery sessions specific for the existing iSCSI portal group. This RPC overwrites the setting by the global parameters for the iSCSI portal group.


Added spdk_sock_is_connected to check whether the socket is currently connected. spdk_sock_group_poll now returns number of events on success.


Added spdk_pci_device_unclaim() function to cleanup pci claim file.


framework_start_init RPC no longer stops the application on error during initialization.


Updated DPDK submodule to DPDK 19.08.


Updated OCF submodule to OCF v19.06

Along with update, new cache mode 'write only' was added.

New cache modes added to use via RPC, wi - write invalidate and wa - write around.

New version of OCF provides fully asynchronous management API.

v19.07: NVMe-oF FC Transport, VMD, NVMe-oF Persistent reservations, Bdev I/O with separate metadata


EXPERIMENTAL: Added ability to mirror writes to persistent write buffer cache to allow for recovery from dirty shutdown event.

Added handling of Asynchronous Nand Management Events (ANM).


EXPERIMENTAL: Added Intel Volume Management Device (VMD) driver. VMD is an integrated controller inside the CPU PCIe root complex. It enables virtual HBAs for the connected NVMe SSDs. spdk_vmd_init() enumerates NVMe SSDs behind VMD device and hook them into SPDK PCI subsystem. spdk_nvme_probe() or spdk_nvme_connect() can be used to connect NVMe driver to the device located at the given transport ID.

To obtain transport ID of NVMe SSD behind VMD spdk_lspci can be used.

Current implementation does not support hotplug.


Blobfs file asynchronous operations were added to public APIs.


A new file API spdk_posix_file_load was added to load file content into a data buffer.

New APIs spdk_dif_ctx_set_data_offset, spdk_dif_verify_stream, spdk_dif_get_range_with_md, spdk_dif_get_length_with_md have been added, and existing APIs spdk_dif_ctx_init, spdk_dif_set_md_interleave_iovs, and spdk_dif_generate_stream have been refined to insert or strip DIF into iovs windows of any alignment.

New APIs spdk_dif_ctx_set_remapped_init_ref_tag, spdk_dif_remap_ref_tag, and spdk_dix_remap_ref_tag have been added to remap DIF reference tag.

New APIs spdk_dif_update_crc32c and spdk_dif_update_crc32c_stream have been added to compute CRC-32C checksum for extended LBA payload.

Bdevperf and bdevio applications now support starting tests with application specific RPCs. Please see helper Python scripts in their respective directories. This is a move towards simpler RPC-only configuration for all main and auxiliary applications.

Legacy INI style configuration for SPDK applications will become deprecated in SPDK 19.10, and removed in SPDK 20.01. Please consider moving to JSON-RPC configuration files and/or RPC driven run-time configuration.


EXPERIMENTAL: A Fibre Channel transport that supports Broadcom HBAs has been added. This depends on the FC HBA driver at See the documentation for more information.

Persistent reservation emulation has been added to the NVMe-oF target. Persistent reservation state is stored in a JSON file on the local filesystem between target restart. To support this, an optional parameter to the RPC method nvmf_subsystem_add_ns called --ptpl-file was added. This allows the user to specify which file to store the persistent reservation state in. Note that this is done per namespace.

The c2h success optimization under which a command capsule response is not sent for reads is turned on by default. A config knob was added to allow disabling the optimization. This will mostly be used for integration testing with 5.0.x kernels while some compatibility fixes make their way down the pipeline for 5.1.x kernels.

The sock priority setting of the TCP connection owned by the tcp transport is added. It is used to optimize the TCP connection performance under designated traffic classes. And the priority is used to differentiate the sock priority between SPDK NVMe-oF TCP target application and other TCP based applications.

Shared receive queue can now be disabled even for NICs that support it using the nvmf_create_transport RPC method parameter no_srq. The actual use of a shared receive queue is predicated on hardware support when this flag is not used.

spdk_nvmf_get_optimal_poll_group was added, which is used to return the optimal poll group for the qpair. And ConnectionScheduler configuration is added into the [Nvmf] section in etc/spdk/ to demonstrate how to configure the connection scheduling strategy among different spdk threads.

Added infrastructure to retrieve global and per poll group NVMf statistics.

DIF strip and insert is now supported for TCP transport. When it is enabled, DIF setting is not exposed to the NVMe-oF initiator, and DIF is attached into data for write I/O and stripped from data for read I/O.

Added a field dif_insert_or_strip to struct spdk_nvmf_transport_opts, and updated the related rpc function nvmf_create_transport to make this configurable parameter available to users. The dif_insert_or_strip is relevant for TCP transport for now and used to configure the DIF strip and insert.

Added infrastructure to retrieve NVMf transport statistics.


The function spdk_notify_get_types() and spdk_notify_get_events() were renamed to spdk_notify_foreach_type() and spdk_notify_foreach_event(), respectively. And update type name of callback accordingly.


The format of the data returned by the get_bdevs_iostat RPC has changed to make it easier to parse. It now returns an object with a "ticks" object and "bdevs" array with the per-bdev statistics.

A new bdev module delay has been added which simulates a drive latency when placed on top of a Null bdev. This module is intended only for testing and can be created using the new RPC bdev_delay_create. That RPC takes the name of the underlying bdev as well as average and p99 latency arguments for both read and write operations. Average latency is defined as a value close to what you would expect a perf tool such as FIO to report back as the mean latency of all I/O submitted to the drive. p99 latency is defined as the value one would expect the drive to see the slowest 1% of I/O report. For underlying drives with already significant latency, the latency values provided to the drive will be additive. This should be taken into account if trying to achieve an artificial latency on top of an nvme drive or aio device.

DIF reference tag remapping is now supported for partition type virtual bdev modules. When using partition type virtual bdevs, block address space is remapped during I/O processing and DIF reference tag is remapped accordingly.

Added spdk_bdev_*_with_md() functions allowing for IO with metadata being transferred in separate buffer. To check support for separate metadata, use spdk_bdev_is_md_separate().

All bdevs now have a UUID. For devices whose backing hardware does not provide a UUID, one is automatically generated. Across runs of SPDK, bdevs whose UUID is automatically generated may change.

A new virtual bdev module compress has been added to provide compression services on top of a thinly provisioned logical volume. See documentation for complete details.


Added an optional parameter --io-queue-requests to RPC set_bdev_nvme_options, which can be used to change the number of requests allocated for one NVMe I/O queue. For very big I/O size, e.g. 128MiB, with this option user will not get an error due to limited requests in NVMe driver layer.

Added spdk_nvme_ctrlr_get_transport_id() to get the transport ID from a previously attached controller.

Nvme Opal library spdk_opal_cmd deprecated. Adding separate command APIs. NVMe Opal library add support for activating locking SP which will make the transaction from "Manufactured-Inactive" state to "Manufactured" state. Upon successfully invoking of this method, lock and unlock features will be enabled. NVMe Opal library add support for locking/unlocking range and list locking range info. NVMe opal library add support for multiuser. Admin can enable user and add user to specific locking range and the user can lock/unlock his range.

Added spdk_nvme_ctrlr_io_cmd_raw_no_payload_build() allowing a caller to pass a completely formed command to an NVMe submission queue (buffer addresses and all). This is supported on the PCIe transport only.

Added spdk_nvme_get_ctrlr_registers() to return a pointer to the virtual address of the NVMe controller registers. This is supported on the PCIe transport only.

Added additional options to the spdk_nvme_ctrlr_alloc_qpair() option parameter structure to allow caller to override the virtual and optionally physical address of the submission and completion queue pair to be created. This is supported on the PCIe transport only.

Added disable_error_logging to struct spdk_nvme_ctrlr_opts, which disables logging of failed requests. By default logging is enabled.

Added spdk_nvme_qpair_print_command(), spdk_nvme_qpair_print_completion() and spdk_nvme_cpl_get_status_string(). Allowing for easier display of error messages.

Added support for NVMe Sanitize command.


The parameter free_space has been added to spdk_ring_enqueue() to wait when the ring is almost full and resume when there is enough space available in the ring.

A new API spdk_mempool_lookup has been added to lookup the memory pool created by the primary process.

Added spdk_pci_get_first_device() and spdk_pci_get_next_device() to allow iterating over PCI devices detected by SPDK. Because of this, all SPDK APIs to attach/detach PCI devices are no longer thread safe. They are now meant to be called from only a single thread only, the same only that called spdk_env_init(). This applies to the newly added APIs as well.


SPDK now supports VPP version 19.04.2, up from VPP 18.01.

VPP socket abstraction now uses VPP Session API, instead of VLC (VPP Communications Library). This allows for better control over sessions and queues. Please see VPP documentation for more details: VPP Host Stack


Add spdk_sock_get_optimal_sock_group(), which returns the optimal sock group for this socket. When a socket is created, it is often assigned to a sock group using spdk_sock_group_add_sock so that a set of sockets can be polled more efficiently. For some network devices, it is optimal to assign particular sockets to specific sock groups. This API is intended to provide the user with that information.

spdk_sock_group_get_ctx() was added to return the context of the spdk_sock_group. spdk_sock_group_create() is updated to allow input the user provided ctx. spdk_sock_set_priority() is added to set the priority of the socket.


Added thread_get_stats RPC method to retrieve existing statistics.

Added nvmf_get_stats RPC method to retrieve NVMf subsystem statistics.

Response buffers for RPC requests are now always pre-allocated, which implies that all spdk_jsonrpc_begin_result() calls always succeed and return a valid buffer for JSON response. RPC calls no longer need to check if the buffer is non-NULL.

Added SPDK_RPC_REGISTER_ALIAS_DEPRECATED to help with deprecation process when renaming existing RPC. First time a deprecated alias is used, it will print a warning message.

RPC get_rpc_methods was renamed rpc_get_methods. The old name is still usable, but is now deprecated.


A snapshot can now be deleted if there is only a single clone on top of it.


Preliminary support for cross compilation is now available. Targeting an older CPU on the same architecture using your native compiler can be accomplished by using the --target-arch option to configure as follows:

./configure --target-arch=broadwell

Additionally, some support for cross-compiling to other architectures has been added via the --cross-prefix argument to configure. To cross-compile, set CC and CXX to the cross compilers, then run configure as follows:

./configure --target-arch=aarm64 --cross-prefix=aarch64-linux-gnu


A security vulnerability has been identified and fixed in SPDK Vhost-SCSI target. A malicious client (e.g. a virtual machine) could send a carefully prepared, invalid I/O request to crash the entire SPDK process. All users of SPDK Vhost-SCSI target are strongly recommended to update. All SPDK versions < 19.07 are affected.

By default, SPDK will now rely on upstream DPDK's rte_vhost instead of its fork located inside SPDK repo. The internal fork is still kept around to support older DPDK versions, but is considered legacy and will be eventually removed.

configure will now automatically use the upstream rte_vhost if the used DPDK version is >= 19.05.

spdk_vhost_init() is now asynchronous and accepts a completion callback.

iscsi target

A security vulnerability has been identified and fixed in SPDK iSCSI target. A malicious client (e.g. an iSCSI initiator) could send a carefully prepared, invalid I/O request to crash the entire SPDK process. All users of SPDK iSCSI target are strongly recommended to update. All SPDK versions < 19.07 are affected.


Exposed spdk_set_thread() in order for applications to associate with SPDK thread when necessary.

Added spdk_thread_destroy() to allow framework polling the thread to release resources associated with that thread.

v19.04: Compression bdev, Notification library, NVMe Opal support


Added asynchronous probe support. New APIs spdk_nvme_probe_async(), spdk_nvme_connect_async() and spdk_nvme_probe_poll_async() were added to enable this feature. spdk_nvme_probe_async() and spdk_nvme_connect_async() return a context associated with the specified controllers. Users then call spdk_nvme_probe_poll_async() until it returns 0, indicating that the operation completed.

A new qpair creation option, delay_pcie_doorbell, was added. This can be passed to spdk_nvme_alloc_io_qpair(). This makes the I/O submission functions, such as spdk_nvme_ns_writev(), skip ringing the submission queue doorbell. Instead the doorbell will be rung as necessary inside spdk_nvme_qpair_process_completions(). This can result in significantly fewer MMIO writes to the doorbell register under heavy load, greatly improving performance.

spdk_nvme_ctrlr_get_regs_cmbsz() was added to report the size of the controller memory buffer, if available.

spdk_nvme_ctrlr_get_flags() was added to return controller feature flags. Two flags are currently tracked: SPDK_NVME_CTRLR_SGL_SUPPORTED SPDK_NVME_CTRLR_SECURITY_SEND_RECV_SUPPORTED

The NVMe hotplug poller is now able to detach devices hot-removed from the system via /sys/bus/pci/devices/<bdf>/remove and /sys/bus/pci/devices/<bdf>/driver/unbind.

Opal support was added for scan, take ownership, revert TPer, and dumping device info. The nvme_manage tool can be used to perform these operations. The public API functions are spdk_nvme_ctrlr_security_receive() and spdk_nvme_ctrlr_security_send(). This module should be considered experimental pending additional features and tests.

The NVMe-oF initiator is now able to transfer IO whose size is more than 128KiB if the corresponding NVMe-oF target allows.


Added new strip_size_kb rpc param on create to replace the more ambiguous strip_size. The strip_size rpc param is deprecated.

Changed the raid bdev product_name from "Pooled Device" to "Raid Volume"


Added spdk_thread_has_pollers() function to verify if there are any registered pollers to be run on the thread. Added spdk_thread_is_idle() function to check if there are any scheduled operations to be performed on the thread at given time.

spdk_thread_create() now takes an optional CPU affinity mask that is passed to the scheduler.

spdk_thread_lib_init() now takes an optional context size. For each thread created, an additional region of memory of this size will be allocated. A pointer to this region of memory can be obtained by calling spdk_thread_get_ctx(). The inverse operation is also available via spdk_thread_get_from_ctx().

spdk_thread_poll() now optionally accepts the current time, in ticks. This can be used to avoid some calls to spdk_get_ticks() internally.

spdk_app_start() now only accepts a single context argument.


An new API spdk_bdev_get_data_block_size has been added to get size of data block except for metadata.

spdk_vbdev_register() has been deprecated. spdk_bdev_register() should be used instead.

A mechanism for acquiring and releasing data buffers from bdev modules, used to perform zero copy operations, was added.

New APIs spdk_bdev_get_md_size(), spdk_bdev_is_md_interleaved(), spdk_bdev_get_dif_type(), spdk_bdev_is_dif_head_of_md(), and spdk_bdev_is_dif_check_enabled() have been added to get metadata and DIF settings.

Bdevs claimed by the examine_config callback will be now further examined in the examine_disk callback.

spdk_bdev_io_get_io_channel() was added as a convenient way to get an io_channel from a bdev_io.


Updated OCF submodule to OCF v19.3.2

Added support for many-to-one configuration for OCF bdev. Multiple core devices can now be cached on single cache device.

Added persistent metadata support, allowing to restore cache state after shutdown. During start of SPDK application, the devices are examined and if OCF metadata is present - appropriate OCF bdevs will be recreated.

Added Write-Back mode support. In this mode, data is first written to caching device and periodically synchronized to the core devices. Dirty data is saved as persistent metadata on cache device, allowing for safe restore during application restart. For more details please see OCF documentation: OpenCAS cache configuration

NVMe-oF Target

Support for per-device shared receive queues in the RDMA transport has been added. It is enabled by default for any device that supports it.

The size of a shared receive queue is defined by transport configuration file parameter MaxSRQDepth and nvmf_create_transport RPC method parameter max_srq_depth. Default size is 4096.

Add model number as parameter to construct_nvmf_subsystem (-d option), rather than using hardcoded define.

DIF passthrough feature has been added. DIF setting of the allocated bdevs is exposed to the NVMe-oF initiator and data with DIF from the NVMe-oF initiator is passed through to the allocated bdevs.


The phys_addr parameter in spdk_malloc() and spdk_zmalloc() has been deprecated. For retrieving physical addresses, spdk_vtophys() should be used instead.

spdk_realloc() has been added to reallocate DMA/shared memory.

spdk_pci_device_is_removed() has been added to let the upper-layer SPDK drivers know that device has a pending external hotremove request.

spdk_env_fini() and spdk_env_dpdk_post_fini() were added to release any resources allocated by spdk_env_init() or spdk_env_dpdk_post_init() respectively. It is expected that common usage of those functions is to call them just before terminating the process.

Added spdk_iommu_is_enabled() to report if SPDK application is using IOMMU for DMA.


Dropped support for DPDK 17.07 and earlier, which SPDK won't even compile with right now.

Updated DPDK submodule to DPDK 19.02.


New get_spdk_version RPC method is introduced to get version info of the running SPDK application.

The start_nbd_disk RPC method now take nbd_device as an optional parameter. If nbd_device is specified, use that specified nbd device. If it's not specified, pick available one.

iSCSI target

DIF strip and insert is now supported. DIF settings are not exposed to the iSCSI initiator. DIF is attached into data for write I/O and stripped from data for read I/O.


Added experimental support for running with the external, upstream rte_vhost library. This can be enabled by configuring SPDK with an --without-internal-vhost-lib flag. The minimum supported rte_vhost version (DPDK version) is 19.05-rc1.

As a result of fuzz testing, a lot of data races in vhost-scsi LUN hotplug path were identified and fixed. Those data races could have potentially resulted in SPDK crashes, RPC hangs, or memory leaks if Vhost-SCSI LUN hotplug RPCs were executed while connected VMs were in the middle of restarting.

The SCSI target id in add_vhost_scsi_lun RPC is now optional. If -1 is passed, the first unoccupied target id will be used.


AIO bdev module can now reap I/O completions directly from userspace, significantly improving the overall performance.


Synchronous IO operations no longer use spdk_io_channel, but instead use spdk_fs_thread_ctx. The behavior is otherwise identical.


Added support for caching multiple bdevs using a single bdev as a cache.


Added the notify library that provides a high performance local event bus between libraries. Example usage was added to bdev module, which reports notifications for added and removed bdevs via RPC.


Added new API spdk_sock_readv() to the sock library for performing vectored reads.


The function spdk_subsystem_init() no longer requires spdk_event as an argument.

Changed API of spdk_subsystem_config_json() to no longer be asynchronous.


A bdev module that issues I/O to kernel block devices using the new io_uring Linux kernel API was added. This module requires liburing.


Options to easily compile with profile guided optimization have been added to configure. To use profile guided optimization with SPDK, run ./configure --with-pgo-capture, build SPDK, then run a workload of your choosing. Then, simply run ./configure --with-pgo-enable and recompile to build using the generated profile data. Profile guided optimization can yield very large performance improvements, especially on GCC 8 and clang 7. This may be combined with link time optimization which has been available under the --enable-lto configure option for several releases.

compression bdev/reduce library

Added "reduce" block compression scheme based on using SSDs for storing compressed blocks of storage and persistent memory for metadata. Please see compression for more details.

v19.01: NVMe-oF TCP/IP Transport, Open Channel SSD Flash Translation Layer, Caching bdev based on OCF, ISA-L Support, DIF/DIX library

ocf bdev

New virtual bdev module based on Open CAS Framework has been added. This module allows for the use of one bdev to act as a high performance cache in front of another bdev. Please see documentation for more details. Only write through mode is currently supported and this feature is considered experimental.

event framework

For spdk_app_parse_args, add return value to the callback which parses application specific command line parameters to protect SPDK applications from crashing by invalid values from user input.

By default, all SPDK applications will now reserve all hugepages at runtime. The pre-reserved memory size can be still set with -s or --mem-size option, although the default value was reduced down to 0.

A custom hugetlbfs directory can now be specified via spdk_app_opts. This can be used to configure hugepages with different sizes, a different size limit, or different access permissions than the system's default hugepage pool. SPDK applications can specify a custom hugetlbfs mount with the --huge-dir option.


spdk_vtophys() has been refactored to accept length of the translated region as a new parameter. The function will now update that parameter with the largest possible value for which the memory is contiguous in the physical memory address space.

The following functions were removed:

  • spdk_pci_nvme_device_attach()
  • spdk_pci_nvme_enumerate()
  • spdk_pci_ioat_device_attach()
  • spdk_pci_ioat_enumerate()
  • spdk_pci_virtio_device_attach()
  • spdk_pci_virtio_enumerate()

They were replaced with generic spdk_pci_device_attach() and spdk_pci_enumerate() which require a new spdk_pci_driver object to be provided. It can be one of the following:

spdk_pci_hook_device() and spdk_pci_unhook_device() were added. Those allow adding a virtual spdk_pci_device into the SPDK PCI subsystem. A virtual device calls provided callbacks for each BAR mapping request or PCI config access. It's attachable with spdk_pci_device_attach() or spdk_pci_enumerate() like any other device.

A new spdk_pause() function was added to pause CPU execution for an implementation specific amount of time. Quoting from DPDK function this is based on: "This call is intended for tight loops which poll a shared resource or wait for an event. A short pause within the loop may reduce the power consumption."

A new public header file env_dpdk.h has been introduced, and function spdk_env_dpdk_post_init is added into it. If user is using DPDK, and already called rte_eal_init, then include include/spdk/env_dpdk.h, and call spdk_env_dpdk_post_init() instead of spdk_env_init.

ISA-L has been added as an SPDK submodule. ISA-L is enabled by default on x86 architecture to accelerate algorithms such as CRC for iSCSI and NVMe-oF. Users may still disable ISA-L by explicitly passing –without-isal to the configure script.


A new uuid API spdk_uuid_copy was added to make a copy of the source uuid.

An new parameter init_crc representing the initial CRC value was added to spdk_crc16_t10dif. The parameter can be used to calculate a CRC value spanning multiple separate buffers.

New DIF APIs were added to generate and verify DIF by byte granularity for both DIF and DIX formats. Among them, DIF with copy APIs will be usable to emulate DIF operations such as DIF insert and strip.

Added spdk_strtol and spdk_strtoll to provide additional error checking around strtol and strtoll.

Added spdk_sprintf_append_realloc and spdk_vsprintf_append_realloc for appending a string with automatic buffer re-allocation.


Wrapper functions spdk_nvme_ctrlr_security_send() and spdk_nvme_ctrlr_security_receive() are introduced to support further security protocol development.

admin_timeout_ms was added to NVMe controller initialization options, users can change the default value when probing a controller.

Add two new fields "header_digest" and "data_digest" in struct spdk_nvme_ctrlr_opts, it will be used to enable the digest support for the NVMe/TCP transport.

Add a new TCP/IP transport(located in lib/nvme/nvme_tcp.c) in nvme driver. With this new transport, it can be used to connect the NVMe-oF target with the same TCP/IP support.

Added API, spdk_nvme_ctrlr_is_discovery(), to indicate whether the ctrlr arg refers to a Discovery Controller or not.

Added an API function spdk_nvme_host_id_parse and corresponding object spdk_nvme_host_id for parsing host address and host service ID arguments on a per connection basis.

The RPC construct_nvme_bdev now allows a user to specify a source address and service id for the host to use when connecting to the controller backing the NVMe bdev.

NVMe-oF Target

The spdk_nvmf_tgt_opts struct has been deprecated in favor of spdk_nvmf_transport_opts. Users will no longer be able to specify target wide I/O parameters. spdk_nvmf_tgt_listen will also no longer implicitly initialize a transport with the default target options (since there are none). Instead, a user must manually instantiate the transport with spdk_nvmf_transport_create prior to calling spdk_nvmf_tgt_listen.

Related to the previous change, the rpc set_nvmf_target_options has been renamed to set_nvmf_target_max_subsystems to indicate that this is the only target option available for the user to edit.

Added fields num_shared_buffers and buf_cache_size in struct spdk_nvmf_transport_opts, and also updated the related rpc function nvmf_create_transport, to make this configurable parameter available to users. The num_shared_buffers is used to configure the shared buffer numbers of the transport used by RDMA or TCP transport. buf_cache_size configures number of shared buffers to cache per poll group.


Add a new TCP/IP transport (located in lib/nvmf/tcp.c). With this transport, the SPDK NVMe-oF target can have a new transport, and can serve the NVMe-oF protocol via TCP/IP from the host.

Added optional mechanism to modify the RDMA transport's behavior when creating protection domains and registering memory. By default, the RDMA transport will use the ibverbs library to create protection domains and register memory. Using spdk_nvme_rdma_init_hooks will subvert that and use an existing registration.


Added enable_bdev_histogram and get_bdev_histogram RPC commands to allow gathering latency data for specified bdev. Please see documentation for more details.

Added required_alignment field to spdk_bdev, that specifies an alignment requirement for data buffers associated with an spdk_bdev_io. Bdev layer will automatically double buffer any spdk_bdev_io that violates this alignment, before the spdk_bdev_io is submitted to the bdev module.

On shutdown, bdev unregister now proceeds in top-down fashion, with claimed bdevs skipped (these will be unregistered later, when virtual bdev built on top of the respective base bdev unclaims it). This allows virtual bdevs to be shut down cleanly as opposed to the previous behavior that didn't differentiate between hotremove and planned shutdown.

The delete_bdev RPC is now deprecated. Users should instead use the specific deletion RPC for the bdev type to be removed (i.e. delete_malloc_bdev).

Added support for separate bandwidth rate limits for read and write to QoS in bdev layer.

Bdev I/O statistics now track unmap operations.

logical volumes

Logical volume bdev can now be marked as read only using set_read_only_lvol_bdev RPC. This allows for basing clones on top of lvol_bdev without first creating a snapshot.

Added option to change method for data erasure when deleting lvol or resizing down. Default of unmapping clusters can now be changed to writing zeroes or no operation.

Added option to change method for erasing data region on lvol store creation. Default of unmapping can now be changed to writing zeroes or no operation.


"trace flags" are now referred to as "log flags" in the SPDK log API. The set_trace_flag, clear_trace_flag and get_trace_flags RPCs are now deprecated, and set_log_flag, clear_log_flag and get_log_flags RPCs have been added.


New trace_record application was added. It can be used to poll spdk trace shm file and append any new trace entries into another specified file. This can help retain those entries that would otherwise be overwritten in the shm file. See Capturing sufficient trace events for more details.

Number of trace entries in circular buffer per lcore can now be assigned by starting SPDK app with argument "--num-trace-entries <NUM>" provided.

New get_tpoint_group_mask RPC was added to get current tpoint_group_mask, and each tpoint group status. New enable_tpoint_group and disable_tpoint_group RPC were added to enable or disable a specific tpoint group.


EXPERIMENTAL: Added basic flash translation layer module allowing for using Open Channel SSDs as block devices. The module is split into the library (located in lib/ftl) and bdev_ftl (lib/bdev/ftl). See the documentation for more details.


A security vulnerability has been identified and fixed in the SPDK vhost target. A malicious vhost client (i.e. virtual machine) could carefully construct a circular descriptor chain which would result in a partial denial of service in the SPDK vhost target. These types of descriptor chains are now properly detected by the vhost target. All SPDK vhost users serving untrusted vhost clients are strongly recommended to upgrade. (Reported by Dima Stepanov and Evgeny Yakovlev.)

Vhost SCSI and Vhost Block devices can now accept multiple connections on the same socket file. Each connection (internally called a vhost session) will have access to the same storage, but will use different virtqueues, different features and possibly different memory.

vhost scsi

SCSI target hotremove can now be performed even without the VIRTIO_SCSI_F_HOTPLUG feature negotiated. Regardless of VIRTIO_SCSI_F_HOTPLUG support, the hotremoval will be still reported through SCSI sense codes.


DPDK submodule was updated to DPDK 18.11. Note that SPDK does not fully leverage the new multi-process device hotplug yet and continues to work the same way it always did.

Dropped support for DPDK 16.07 and earlier, which SPDK won't even compile with right now.


The following RPC commands deprecated in the previous release are now removed:

  • construct_virtio_user_scsi_bdev
  • construct_virtio_pci_scsi_bdev
  • construct_virtio_user_blk_bdev
  • construct_virtio_pci_blk_bdev
  • remove_virtio_scsi_bdev
  • construct_nvmf_subsystem


The configure options --with-raid and --without-raid that were deprecated in the previous release are now removed.


Starting nbd using spdk_nbd_start is now performed asynchronously.

net framework

Net framework initialization and finish is now done asynchronously.


Added spdk_rpc_is_method_allowed function for checking whether method is permitted in a given state. Added spdk_rpc_get_state to check current state of RPC server. RPC wait_subsystem_init has been added to allow clients to block until all subsystems are initialized.

json rpc

JSON RPC client is now running in non-blocking mode. Requests are sent and received during spdk_jsonrpc_client_poll. JSON RPC server can now receive a callback on connection termination or server shutdown using spdk_jsonrpc_conn_add_close_cb and spdk_jsonrpc_conn_del_close_cb.

v18.10: Dynamic memory allocation, Crypto Virtual Bdev, jsonrpc-client, SPDKCLI iSCSI and NVMe-oF support


spdk_nvme_ctrlr_cmd_security_send() and spdk_nvme_ctrlr_cmd_security_receive() were added to support sending or receiving security protocol data to or from nvme controller.

spdk_nvme_ns_get_extended_sector_size() was added. This function includes the metadata size per sector (if any). spdk_nvme_ns_get_sector_size() still returns only the data size per sector, not including metadata.

New send_nvme_cmd RPC was added to allow sending NVMe commands directly to NVMe controller. See the send_nvme_cmd documentation for more details.

Build System

New configure options, --with-shared and --without-shared [default], provide the capability to build, or not, SPDK shared libraries. This includes the single SPDK shared lib encompassing all of the SPDK static libs as well as individual SPDK shared libs corresponding to each of the SPDK static ones. Although the production of the shared libs conforms with conventional version naming practices, such naming does not at this time confer any SPDK ABI compatibility claims.


spdk_bdev_alias_del_all() was added to delete all alias from block device.

A new virtual bdev module has been added to perform at rest data encryption using the DPDK CryptoDev Framework. The module initially uses a software AESNI CBC cipher with experimental support for the Intel QAT hardware accelerator also currently implemented with support for CBC cipher. Future work may include additional ciphers as well as consideration for authentication.

The RAID virtual bdev module is now always enabled by default. The configure –with-raid and –without-raid options are now ignored and deprecated and will be removed in the next release.

Enforcement of bandwidth limits for quality of service (QoS) has been added to the bdev layer. See the new set_bdev_qos_limit documentation for more details. The previous set_bdev_qos_limit_iops RPC method introduced at 18.04 release has been deprecated. The new set_bdev_qos_limit RPC method can support both bandwidth and IOPS limits.

spdk_bdev_config_json() and corresponding get_bdevs_config RPC was removed.

Environment Abstraction Layer and Event Framework

The size parameter of spdk_mem_map_translate is now a pointer. This allows the function to report back the actual size of the translation relative to the original request made by the user.

A new structure spdk_mem_map_ops has been introduced to hold memory map related callbacks. This structure is now passed as the second argument of spdk_mem_map_alloc in lieu of the notify callback.

DPDK 18.08

The DPDK submodule has been updated to the DPDK 18.08 release. SPDK will now automatically utilize DPDK's dynamic memory management with DPDK versions >= 18.05.1.

Hugepages can be still reserved with [-s|--mem-size <size>] option at application startup, but once we use them all up, instead of failing user allocations with -ENOMEM, we'll try to dynamically reserve even more. This allows starting SPDK with --mem-size 0 and using only as many hugepages as it is really needed.

Due to this change, the memory buffers returned by spdk_*malloc() are no longer guaranteed to be physically contiguous.


I/OAT driver can now reinitialize I/OAT channels after encountering DMA errors.

iscsi target

Parameter names of set_iscsi_options and get_iscsi_global_params RPC method for CHAP authentication in discovery sessions have been changed to align with construct_target_node RPC method. Old names are still usable but will be removed in future release.

set_iscsi_discovery_auth and set_iscsi_target_node_auth RPC methods have been added to set CHAP authentication for discovery sessions and existing target nodes, respectively.

The SPDK iSCSI target supports an AuthFile which can be used to load CHAP shared secrets when the iSCSI target starts. SPDK previously provided a default location for this file (/usr/local/etc/spdk/auth.conf) if none was specified. This default has been removed. Users must now explicitly specify the location of this file to load CHAP shared secrets from a file, or use the related iSCSI RPC methods to add them at runtime.

iscsi initiator

The SPDK iSCSI initiator is no longer considered experimental and becomes a first-class citizen among bdev modules. The basic usage has been briefly described in the bdev user guide: iSCSI bdev


The SPDK application framework can now parse long name command line parameters. Most single-character parameters have a long name equivalent now. See the Command Line Parameters documentation for details or use the --help command line parameter to list all available params.

bdevperf -s param (io size) was renamed to -o as -s had been already used by existing apps for memory size.

bdevio can now accept all SPDK command line parameters. The config now has to be provided with -c or --config param.

The following ioat/perf and nvme/perf parameters were renamed as well: -s (io size) to -o -d (mem size) to -s

The ReactorMask config file parameter has been deprecated. Users should use the -m or –cpumask command line option to specify the CPU core mask for the application.

Default config file pathnames have been removed from iscsi_tgt, nvmf_tgt and vhost. Config file pathnames may now only be specified using the -c command line option.

Users may no longer set DPDK_DIR in their environment to specify the location of the DPDK installation used to build SPDK. Using DPDK_DIR has not been the documented nor recommended way to specify the DPDK location for several releases, but removing it ensures no unexpected surprises for users who may have DPDK_DIR defined for other reasons. Users should just use the "configure" script to specify the DPDK location before building SPDK.

Although we know that many developers still use Python 2 we are officially switching to Python3 with requirement that all new code must be valid also for Python 2 up to the EOL which is year 2020.

Invoking interpreter explicitly is forbidden for executable scripts. There is no need to use syntax like "python ./scripts/". All executable scripts must contain proper shebang pointing to the right interpreter. Scripts without shebang mustn't be executable.

A Python script has been added to enable conversion of old INI config file to new JSON-RPC config file format. This script can be found at scripts/ Example how this script can be used:

cat old_format.ini | scripts/ > new_json_format.json


Two additional parameters were added to spdk_sock_get_addr() for the server port and client port. These parameters are named "sport" and "cport" respectively.


The following RPC commands have been deprecated:

  • construct_virtio_user_scsi_bdev
  • construct_virtio_pci_scsi_bdev
  • construct_virtio_user_blk_bdev
  • construct_virtio_pci_blk_bdev
  • remove_virtio_scsi_bdev

The construct_virtio_* ones were replaced with a single construct_virtio_dev command that can create any type of Virtio bdev(s). remove_virtio_scsi_bdev was replaced with remove_virtio_bdev that can delete both Virtio Block and SCSI devices.


spdk_file_get_id() returning unique ID for the file was added.


Added jsonrpc-client C library intended for issuing RPC commands from applications.

Added API enabling iteration over JSON object:


Blobstore I/O operations are now based on io_units, instead of blobstore page size. The io_unit size is now the same as the underlying block device's block size. Logical volumes built on a block device with 512B block size can now be used as boot devices in QEMU.


The SPDKCLI interactive command tool for managing SPDK is no longer considered experimental. Support for the iSCSI and NVMe-oF targets has been added.

v18.07: Raid, Infrastructure Improvements, Bug Fixes


A new public header file bdev_module.h has been introduced to facilitate the development of new bdev modules. This header includes an interface for the spdk_bdev_part and spdk_bdev_part_base objects to enable the creation of multiple virtual bdevs on top of a single base bdev and should act as the primary API for module authors.

spdk_bdev_get_opts() and spdk_bdev_set_opts() were added to set bdev-wide options.

A mechanism for handling out of memory condition errors (ENOMEM) returned from I/O submission requests at the bdev layer has been added. See spdk_bdev_queue_io_wait().

The spdk_bdev_get_io_stat() function now returns cumulative totals instead of resetting on each call. This allows multiple callers to query I/O statistics without conflicting with each other. Existing users will need to adjust their code to record the previous I/O statistics to calculate the delta between calls.

I/O queue depth tracking and samples options have been added. See spdk_bdev_get_qd(), spdk_bdev_get_qd_sampling_period(), and spdk_bdev_set_qd_sampling_period().

RAID module

A new bdev module called "raid" has been added as experimental module which aggregates underlying NVMe bdevs and exposes a single raid bdev. Please note that vhost will not work with this module because it does not yet have support for multi-element io vectors.


The debug log component flag available on several SPDK applications has been renamed from -t to -L to prevent confusion with tracepoints and to allow the option to be added to tools that already use -t to mean something else.


A new function, spdk_bs_dump(), has been added that dumps all of the contents of a blobstore to a file pointer. This includes the metadata and is very useful for debugging.

Two new operations have been added for thin-provisioned blobs. spdk_bs_inflate_blob() will allocate clusters for all thinly provisioned regions of the blob and populate them with the correct data by reading from the backing blob(s). spdk_bs_blob_decouple_parent() works similarly, but will only allocate clusters that correspond to data in the blob's immediate parent. Clusters allocated to grandparents or that aren't allocated at all will remain thin-provisioned.


Changed the return type of spdk_file_truncate() from void to int to allow the propagation of ENOMEM errors.

NVMe Driver

The new API functions spdk_nvme_qpair_add_cmd_error_injection() and spdk_nvme_qpair_remove_cmd_error_injection() have been added for NVMe error emulation. Users can set a specified command to fail with a particular error status.

Changed the name timeout_sec parameter to timeout_us in spdk_nvme_ctrlr_register_timeout_callback(), and also changed the type from uint32_t to uint64_t. This will give users more fine-grained control over the timeout period.

Basic support for Open Channel SSDs was added. See nvme_ocssd.h

NVMe Over Fabrics

The spdk_nvmf_tgt_destroy() function is now asynchronous and takes a callback as a parameter.

spdk_nvmf_qpair_disconnect() was added to allow the user to disconnect qpairs.

spdk_nvmf_subsystem_get_max_namespaces() was added to query the maximum allowed number of namespaces for a given subsystem.

Build System

The build system now generates a combined shared library ( that may be used in place of the individual static libraries (libspdk_*.a). The combined library includes all components of SPDK and is intended to make linking against SPDK easier. The static libraries are also still provided for users that prefer to link only the minimal set of components required.

git pre-commit and pre-push hooks

The pre-commit hook will run scripts/ and verify there are no formatting errors before allowing git commit to run. The pre-push hook runs make CONFIG_WERROR=y with and without CONFIG_DEBUG=y using both the gcc and clang compiler before allowing git push to run. Following each DEBUG build test/unit/ is run and verified. Results are recorded in the make.log file.

To enable type: 'git config core.hooksPath .githooks'. To override after configuration use the git --no-verify flag.


The start_nbd_disk RPC method now returns the path to the kernel NBD device node rather than always returning true.

DPDK 18.05

The DPDK submodule has been rebased on the DPDK 18.05 release. DPDK 18.05 supports dynamic memory allocation, but due to some issues found after the DPDK 18.05 release, that support is not enabled for SPDK 18.07. Therefore, SPDK 18.07 will continue to use the legacy memory allocation model. The plan is to enable dynamic memory allocation after the DPDK 18.08 release which should fix these issues.

Environment Abstraction Layer and Event Framework

The spdk_mem_map_translate() function now takes a size parameter to indicate the size of the memory region. This can be used by environment implementations to validate the requested translation.

The I/O Channel implementation has been moved to its own library - lib/thread. The public API that was previously in spdk/io_channel.h is now in spdk/thread.h The file spdk/io_channel.h remains and includes spdk/thread.h.

spdk_reactor_get_tsc_stats was added to return interesting statistics for each reactor.


IOAT for copy engine is disabled by default. It can be enabled by specifying the Enable option with "Yes" in [Ioat] section of the configuration file. The Disable option is now deprecated and will be removed in a future release.

v18.04: Logical Volume Snapshot/Clone, iSCSI Initiator, Bdev QoS, VPP Userspace TCP/IP


The SPDK vhost-scsi, vhost-blk and vhost-nvme applications have fixes to address the DPDK rte_vhost vulnerability CVE-2018-1059. Please see this security advisory for additional information on the DPDK vulnerability.

Workarounds have been added to ensure vhost compatibility with QEMU 2.12.

EXPERIMENTAL: Support for vhost-nvme has been added to the SPDK vhost target. See the vhost documentation for more details.

Unified Target Application

A new unified SPDK target application, spdk_tgt, has been added. This application combines the functionality of several existing SPDK applications, including the iSCSI target, NVMe-oF target, and vhost target. The new application can be managed through the existing configuration file and JSON-RPC methods.


spdk_mempool_get_bulk() has been added to wrap DPDK rte_mempool_get_bulk().

New memory management functions spdk_malloc(), spdk_zmalloc(), and spdk_free() have been added. These new functions have a flags parameter that allows the user to specify whether the allocated memory needs to be suitable for DMA and whether it should be shared across processes with the same shm_id. The new functions are intended to replace spdk_dma_malloc() and related functions, which will eventually be deprecated and removed.


A new optional bdev module interface function, init_complete, has been added to notify bdev modules when the bdev subsystem initialization is complete. This may be useful for virtual bdevs that require notification that the set of initialization examine() calls is complete.

The bdev layer now allows modules to provide an optional per-bdev UUID, which can be retrieved with the spdk_bdev_get_uuid() function.

Enforcement of IOPS limits for quality of service (QoS) has been added to the bdev layer. See the set_bdev_qos_limit_iops documentation for more details.


The [Rpc] configuration file section, which was deprecated in v18.01, has been removed. Users should switch to the -r command-line parameter instead.

The JSON-RPC server implementation now allows up to 32 megabyte responses, growing as needed; previously, the response was limited to 32 kilobytes.


EXPERIMENTAL: New SPDKCLI interactive command tool for managing SPDK is available. See the SPDKCLI documentation for more details.

NVMe Driver

EXPERIMENTAL: Support for WDS and RDS capable CMBs in NVMe controllers has been added. This support is experimental pending a functional allocator to free and reallocate CMB buffers.

spdk_nvme_ns_get_uuid() has been added to allow retrieval of per-namespace UUIDs when available.

New API functions spdk_nvme_ctrlr_get_first_active_ns() and spdk_nvme_ctrlr_get_next_active_ns() have been added to iterate active namespaces, as well as spdk_nvme_ctrlr_is_active_ns() to check if a namespace ID is active.

NVMe-oF Target

Namespaces may now be assigned unique identifiers via new optional eui64 and nguid parameters to the nvmf_subsystem_add_ns RPC method. Additionally, the NVMe-oF target automatically exposes the backing bdev's UUID as the namespace UUID when available.

spdk_nvmf_subsystem_remove_ns() is now asynchronous and requires a callback to indicate completion.


A number of functions have been renamed:

The old names still exist but are deprecated. They will be removed in the v18.07 release.

spdk_blob_resize() is now an asynchronous operation to enable resizing a blob while I/O are in progress to that blob on other threads. An explicit spdk_blob_sync_md() is still required to sync the updated metadata to disk.

Logical Volumes

A new destroy_lvol_bdev RPC method to delete logical volumes has been added.

Lvols now have their own UUIDs which replace previous LvolStoreUUID_BlobID combination.

New Snapshot and Clone functionalities have been added. User may create Snapshots of existing Lvols and Clones of existing Snapshots. See the lvol snapshots documentation for more details.

Resizing logical volumes is now supported via the resize_lvol_bdev RPC method.


A set of changes were made in the SPDK's lib code altering instances of calls to exit() and abort() to return a failure instead wherever reasonably possible.

spdk_app_start() no longer exit()'s on an internal failure, but instead returns a non-zero error status.

spdk_app_parse_args() no longer exit()'s on help, '-h', or an invalid option, but instead returns SPDK_APP_PARSE_ARGS_HELP and SPDK_APP_PARSE_ARGS_FAIL, respectively, and SPDK_APP_PARSE_ARGS_SUCCESS on success.

spdk_pci_get_device() has been deprecated and will be removed in SPDK v18.07.

I/O Channels

The prototype for spdk_poller_fn() has been modified; it now returns a value indicating whether or not the poller did any work. Existing pollers will need to be updated to return a value.

iSCSI Target

The SPDK iSCSI target now supports the Vector Packet Processing (VPP) framework userspace TCP/IP stack. See the iSCSI VPP documentation for more details.

iSCSI initiator

An iSCSI initiator bdev module has been added to SPDK. This module should be considered experimental pending additional features and tests. More details can be found in lib/bdev/iscsi/README.


The persistent memory (PMDK) bdev module is now enabled using --with-pmdk instead of --with-nvml. This reflects the renaming of the persistent memory library from NVML to PMDK.

Virtio Block driver

A userspace driver for Virtio Block devices has been added. It was built on top of the Virtio library and can be managed similarly to the Virtio SCSI driver. See the Virtio Block reference for more information.

Virtio with 2MB hugepages

The previous 1GB hugepage limitation has now been lifted. A new -g command-line option enables SPDK Virtio to work with 2MB hugepages. See 2MB hugepages for details.

v18.01: Blobstore Thin Provisioning

Build System

The build system now includes a make install rule, including support for the common DESTDIR and prefix variables as used in other build systems. Additionally, the prefix may be set via the configure --prefix option. Example: make install prefix=/usr.


A JSON RPC listener is now enabled by default using a UNIX domain socket at /var/tmp/spdk.sock. A -r option command line option has been added to enable an alternative UNIX domain socket location, or a TCP port in the format ip_addr:tcp_port (i.e. The Rpc configuration file section is now deprecated and will be removed in the v18.04 release.

I/O Channels

spdk_poller_register() and spdk_poller_unregister() were moved from the event framework (include/spdk/event.h) to the I/O channel library (include/spdk/io_channel.h). This allows code that doesn't depend on the event framework to request registration and unregistration of pollers.

spdk_for_each_channel() now allows asynchronous operations during iteration. Instead of immediately continuing the interaction upon returning from the iteration callback, the user must call spdk_for_each_channel_continue() to resume iteration.

Block Device Abstraction Layer (bdev)

The poller abstraction was removed from the bdev layer. There is now a general purpose abstraction for pollers available in include/spdk/io_channel.h


A set of changes were made in the SPDK's lib code altering, instances of calls to exit() and abort() to return a failure instead wherever reasonably possible. This has resulted in return type changes of the API for:

  • spdk_env_init() from type void to int.
  • spdk_mem_map_init() from type void to int.

Applications making use of these APIs should be modified to check for a non-zero return value instead of relying on them to fail without return.

NVMe Driver

SPDK now supports hotplug for vfio-attached devices. But there is one thing keep in mind: Only physical removal events are supported; removing devices via the sysfs remove file will not work.

NVMe-oF Target

Subsystems are no longer tied explicitly to CPU cores. Instead, connections are handed out to the available cores round-robin. The "Core" option in the configuration file has been removed.


A number of functions have been renamed:

The function signature of spdk_blob_close() has changed. It now takes a struct spdk_blob * argument rather than struct spdk_blob **.

The function signature of spdk_bs_iter_next() has changed. It now takes a struct spdk_blob * argument rather than struct spdk_blob **.

Thin provisioning support has been added to the blobstore. It can be enabled by setting the thin_provision flag in struct spdk_blob_opts when calling spdk_bs_create_blob_ext().

NBD device

The NBD application (test/lib/bdev/nbd) has been removed; Same functionality can now be achieved by using the test/app/bdev_svc application and start_nbd_disk RPC method. See the GPT documentation for more details.

FIO plugin

SPDK fio_plugin now supports FIO 3.3. The support for previous FIO 2.21 has been dropped, although it still remains to work for now. The new FIO contains huge amount of bugfixes and it's recommended to do an update.

Virtio library

Previously a part of the bdev_virtio module, now a separate library. Virtio is now available via spdk_internal/virtio.h file. This is an internal interface to be used when implementing new Virtio backends, namely Virtio-BLK.


The MinConnectionIdleInterval parameter has been removed, and connections are no longer migrated to an epoll/kqueue descriptor on the master core when idle.

v17.10: Logical Volumes

New dependencies

libuuid was added as new dependency for logical volumes.

libnuma is now required unconditionally now that the DPDK submodule has been updated to DPDK 17.08.

Block Device Abstraction Layer (bdev)

An fio plugin was added that can route I/O to the bdev layer. See the plugin documentation for more information.

spdk_bdev_unmap() was modified to take an offset and a length in bytes as arguments instead of requiring the user to provide an array of SCSI unmap descriptors. This limits unmaps to a single contiguous range.

spdk_bdev_write_zeroes() was introduced. It ensures that all specified blocks will be zeroed out. If a block device doesn't natively support a write zeroes command, the bdev layer emulates it using write commands.

New API functions that accept I/O parameters in units of blocks instead of bytes have been added:

The bdev layer now handles temporary out-of-memory I/O failures internally by queueing the I/O to be retried later.

Linux AIO bdev

The AIO bdev now allows the user to override the auto-detected block size.

NVMe driver

The NVMe driver now recognizes the NVMe 1.3 Namespace Optimal I/O Boundary field. NVMe 1.3 devices may report an optimal I/O boundary, which the driver will take into account when splitting I/O requests.

The HotplugEnable option in [Nvme] sections of the configuration file is now "No" by default. It was previously "Yes".

The NVMe library now includes a spdk_nvme_ns_get_ctrlr() function which returns the NVMe Controller associated with a given namespace.

The NVMe library now allows the user to specify a host identifier when attaching to a controller. The host identifier is used as part of the Reservations feature, as well as in the NVMe-oF Connect command. The default host ID is also now a randomly-generated UUID, and the default host NQN uses the host ID to generate a UUID-based NQN.

spdk_nvme_connect() was added to allow the user to connect directly to a single NVMe or NVMe-oF controller.

NVMe-oF Target (nvmf_tgt)

The NVMe-oF target no longer requires any in-capsule data buffers to run, and the feature is now entirely optional. Previously, at least 4 KiB in-capsule data buffers were required.

NVMe-oF subsystems have a new configuration option, AllowAnyHost, to control whether the host NQN whitelist is enforced when accepting new connections. If no Host options have been specified and AllowAnyHost is disabled, the connection will be denied; this is a behavior change from previous releases, which allowed any host NQN to connect if the Host list was empty. AllowAnyHost is disabled by default.

NVMe-oF namespaces may now be assigned arbitrary namespace IDs, and the number of namespaces per subsystem is no longer limited.

The NVMe-oF target now supports the Write Zeroes command.

Environment Abstraction Layer

A new default value, SPDK_MEMPOOL_DEFAULT_CACHE_SIZE, was added to provide additional clarity when constructing spdk_mempools. Previously, -1 could be passed and the library would choose a reasonable default, but this new value makes it explicit that the default is being used.


The blobstore super block now contains a bstype field to identify the type of the blobstore. Existing code should be updated to fill out bstype when calling spdk_bs_init() and spdk_bs_load().

spdk_bs_destroy() was added to allow destroying blobstore on device with an initialized blobstore.

spdk_bs_io_readv_blob() and spdk_bs_io_writev_blob() were added to enable scattered payloads.

A CLI tool for blobstore has been added, allowing basic operations through either command line or shell interface. See the blobcli documentation for more details.

Event Framework

The ability to set a thread name, previously only used by the reactor code, is now part of the spdk_thread_allocate() API. Users may specify a thread name which will show up in tools like gdb.


The spdk_trace_dump() function now takes a new parameter to allow the caller to specify an output file handle (stdout or stderr, for example).

Logical Volumes

Logical volumes library built on top of SPDK blobstore has been added. It is possible to create logical volumes on top of other devices using RPC.

See the logical volumes documentation for more information.

Persistent Memory

A new persistent memory bdev type has been added. The persistent memory block device is built on top of libpmemblk. It is possible to create pmem devices on top of pmem pool files using RPC.

See the Pmem Block Device documentation for more information.

Virtio SCSI driver

A userspace driver for Virtio SCSI devices has been added. The driver is capable of creating block devices on top of LUNs exposed by another SPDK vhost-scsi application.

See the Virtio SCSI documentation and Getting Started guide for more information.

Vhost target

The vhost target application now supports live migration between QEMU instances.

v17.07: Build system improvements, userspace vhost-blk target, and GPT bdev

Build System

A configure script has been added to simplify the build configuration process. The existing CONFIG file and make CONFIG_... options are also still supported. Run ./configure --help for information about available configuration options.

A DPDK submodule has been added to make building SPDK easier. If no --with-dpdk option is specified to configure, the SPDK build system will automatically build a known-good configuration of DPDK with the minimal options enabled. See the Building section of for more information.

A Vagrant setup has been added to make it easier to develop and use SPDK on systems without suitable NVMe hardware. See the Vagrant section of for more information.

Userspace vhost-blk target

The vhost library and example app have been updated to support the vhost-blk protocol in addition to the existing vhost-scsi protocol. See the vhost documentation for more details.

Block device abstraction layer (bdev)

A GPT virtual block device has been added, which automatically exposes GPT partitions with a special SPDK-specific partition type as bdevs. See the GPT bdev documentation for more information.

NVMe driver

The NVMe driver has been updated to support recent Intel SSDs, including the Intel® Optane™ SSD DC P4800X series.

A workaround has been added for devices that failed to recognize register writes during controller reset.

The NVMe driver now allocates request tracking objects on a per-queue basis. The number of requests allowed on an I/O queue may be set during spdk_nvme_probe() by modifying io_queue_requests in the opts structure.

The SPDK NVMe fio_plugin has been updated to support multiple threads (numjobs).

spdk_nvme_ctrlr_alloc_io_qpair() has been modified to allow the user to override controller-level options for each individual I/O queue pair. Existing callers with qprio == 0 can be updated to:

... = spdk_nvme_ctrlr_alloc_io_qpair(ctrlr, NULL, 0);

Callers that need to specify a non-default qprio should be updated to:

struct spdk_nvme_io_qpair_opts opts;
spdk_nvme_ctrlr_get_default_io_qpair_opts(ctrlr, &opts, sizeof(opts));
opts.qprio = SPDK_NVME_QPRIO_...;
... = spdk_nvme_ctrlr_alloc_io_qpair(ctrlr, &opts, sizeof(opts));

Environment Abstraction Layer

The environment abstraction layer has been updated to include several new functions in order to wrap additional DPDK functionality. See include/spdk/env.h for the current set of functions.

SPDK Performance Analysis with Intel® VTune™ Amplifier

Support for SPDK performance analysis has been added to Intel® VTune™ Amplifier 2018.

This analysis provides:

  • I/O performance monitoring (calculating standard I/O metrics like IOPS, throughput, etc.)
  • Tuning insights on the interplay of I/O and compute devices by estimating how many cores would be reasonable to provide for SPDK to keep up with a current storage workload.

See the VTune Amplifier documentation for more information.

v17.03: Blobstore and userspace vhost-scsi target

Blobstore and BlobFS

The blobstore is a persistent, power-fail safe block allocator designed to be used as the local storage system backing a higher-level storage service. See the blobstore documentation for more details.

BlobFS adds basic filesystem functionality like filenames on top of the blobstore. This release also includes a RocksDB Env implementation using BlobFS in place of the kernel filesystem. See the BlobFS documentation for more details.

Userspace vhost-scsi target

A userspace implementation of the QEMU vhost-scsi protocol has been added. The vhost target is capable of exporting SPDK bdevs to QEMU-based VMs as virtio devices. See the vhost documentation for more details.

Event framework

The overhead of the main reactor event loop was reduced by optimizing the number of calls to spdk_get_ticks() per iteration.

NVMe library

The NVMe library will now automatically split readv/writev requests with scatter-gather lists that do not map to valid PRP lists when the NVMe controller does not natively support SGLs.

The identify and perf NVMe examples were modified to add a consistent format for specifying remote NVMe over Fabrics devices via the -r option. This is implemented using the new spdk_nvme_transport_id_parse() function.

iSCSI Target

The [Nvme] section of the configuration file was modified to remove the BDF directive and replace it with a TransportID directive. Both local (PCIe) and remote (NVMe-oF) devices can now be specified as the backing block device. A script to generate an entire [Nvme] section based on the local NVMe devices attached was added at scripts/

NVMe-oF Target

The [Nvme] section of the configuration file was modified to remove the BDF directive and replace it with a TransportID directive. Both local (PCIe) and remote (NVMe-oF) devices can now be specified as the backing block device. A script to generate an entire [Nvme] section based on the local NVMe devices attached was added at scripts/

v16.12: NVMe over Fabrics host, hotplug, and multi-process

NVMe library

The NVMe library has been changed to create its own request memory pool rather than requiring the user to initialize the global request_mempool variable. Apps can be updated by simply removing the initialization of request_mempool. Since the NVMe library user no longer needs to know the size of the internal NVMe request structure to create the pool, the spdk_nvme_request_size() function was also removed.

The spdk_nvme_ns_cmd_deallocate() function was renamed and extended to become spdk_nvme_ns_cmd_dataset_management(), which allows access to all of the NVMe Dataset Management command's parameters. Existing callers can be updated to use spdk_nvme_ns_cmd_dataset_management() with SPDK_NVME_DSM_ATTR_DEALLOCATE as the type parameter.

The NVMe library SGL callback prototype has been changed to return virtual addresses rather than physical addresses. Callers of spdk_nvme_ns_cmd_readv() and spdk_nvme_ns_cmd_writev() must update their next_sge_fn callbacks to match.

The NVMe library now supports NVMe over Fabrics devices in addition to the existing support for local PCIe-attached NVMe devices. For an example of how to enable NVMe over Fabrics support in an application, see examples/nvme/identify and examples/nvme/perf.

Hot insert/remove support for NVMe devices has been added. To enable NVMe hotplug support, an application should call the spdk_nvme_probe() function on a regular basis to probe for new devices (reported via the existing probe_cb callback) and removed devices (reported via a new remove_cb callback). Hotplug is currently only supported on Linux with the uio_pci_generic driver, and newly-added NVMe devices must be bound to uio_pci_generic by an external script or tool.

Multiple processes may now coordinate and use a single NVMe device simultaneously using DPDK Multi-process Support.

NVMe over Fabrics target (nvmf_tgt)

The nvmf_tgt configuration file format has been updated significantly to enable new features. See the example configuration file etc/spdk/ for more details on the new and changed options.

The NVMe over Fabrics target now supports virtual mode subsystems, which allow the user to export devices from the SPDK block device abstraction layer as NVMe over Fabrics subsystems. Direct mode (raw NVMe device access) is also still supported, and a single nvmf_tgt may export both types of subsystems simultaneously.

Block device abstraction layer (bdev)

The bdev layer now supports scatter/gather read and write I/O APIs, and the NVMe blockdev driver has been updated to support scatter/gather. Apps can use the new scatter/gather support via the spdk_bdev_readv() and spdk_bdev_writev() functions.

The bdev status returned from each I/O has been extended to pass through NVMe or SCSI status codes directly in cases where the underlying device can provide a more specific status code.

A Ceph RBD (RADOS Block Device) blockdev driver has been added. This allows the iscsi_tgt and nvmf_tgt apps to export Ceph RBD volumes as iSCSI LUNs or NVMe namespaces.

General changes

libpciaccess has been removed as a dependency and DPDK PCI enumeration is used instead. Prior to DPDK 16.07 enumeration by class code was not supported, so for earlier DPDK versions, only Intel SSD DC P3x00 devices will be discovered by the NVMe library.

The env environment abstraction library has been introduced, and a default DPDK-based implementation is provided as part of SPDK. The goal of the env layer is to enable use of alternate user-mode memory allocation and PCI access libraries. See doc/ for more details.

The build process has been modified to produce all of the library files in the build/lib directory. This is intended to simplify the use of SPDK from external projects, which can now link to SPDK libraries by adding the build/lib directory to the library path via -L and linking the SPDK libraries by name (for example, -lspdk_nvme -lspdk_log -lspdk_util).

nvmf_tgt and iscsi_tgt now have a JSON-RPC interface, which allows the user to query and modify the configuration at runtime. The RPC service is disabled by default, since it currently does not provide any authentication or security mechanisms; it should only be enabled on systems with controlled user access behind a firewall. An example RPC client implemented in Python is provided in scripts/

v16.08: iSCSI target, NVMe over Fabrics maturity

This release adds a userspace iSCSI target. The iSCSI target is capable of exporting NVMe devices over a network using the iSCSI protocol. The application is located in app/iscsi_tgt and a documented configuration file can be found at etc/spdk/

This release also significantly improves the existing NVMe over Fabrics target.

  • The configuration file format was changed, which will require updates to any existing nvmf.conf files (see etc/spdk/
    • SubsystemGroup was renamed to Subsystem.
    • AuthFile was removed (it was unimplemented).
    • nvmf_tgt was updated to correctly recognize NQN (NVMe Qualified Names) when naming subsystems. The default node name was changed to reflect this; it is now "".
    • Port and Host sections were merged into the Subsystem section
    • Global options to control max queue depth, number of queues, max I/O size, and max in-capsule data size were added.
    • The Nvme section was removed. Now a list of devices is specified by bus/device/function directly in the Subsystem section.
    • Subsystems now have a Mode, which can be Direct or Virtual. This is an attempt to future-proof the interface, so the only mode supported by this release is "Direct".
  • Many bug fixes and cleanups were applied to the nvmf_tgt app and library.
  • The target now supports discovery.

This release also adds one new feature and provides some better examples and tools for the NVMe driver.

  • The Weighted Round Robin arbitration method is now supported. This allows the user to specify different priorities on a per-I/O-queue basis. To enable WRR, set the arb_mechanism field during spdk_nvme_probe().
  • A simplified "Hello World" example was added to show the proper way to use the NVMe library API; see examples/nvme/hello_world/hello_world.c.
  • A test for measuring software overhead was added. See test/lib/nvme/overhead.

v16.06: NVMf userspace target

This release adds a userspace NVMf (NVMe over Fabrics) target, conforming to the newly-released NVMf 1.0/NVMe 1.2.1 specification. The NVMf target exports NVMe devices from a host machine over the network via RDMA. Currently, the target is limited to directly exporting physical NVMe devices, and the discovery subsystem is not supported.

This release includes a general API cleanup, including renaming all declarations in public headers to include a spdk prefix to prevent namespace clashes with user code.

  • NVMe
    • The nvme_attach() API was reworked into a new probe/attach model, which moves device detection into the NVMe library. The new API also allows parallel initialization of NVMe controllers, providing a major reduction in startup time when using multiple controllers.
    • I/O queue allocation was changed to be explicit in the API. Each function that generates I/O requests now takes a queue pair (spdk_nvme_qpair *) argument, and I/O queues may be allocated using spdk_nvme_ctrlr_alloc_io_qpair(). This allows more flexible assignment of queue pairs than the previous model, which only allowed a single queue per thread and limited the total number of I/O queues to the lowest number supported on any attached controller.
    • Added support for the Write Zeroes command.
    • examples/nvme/perf can now report I/O command latency from the the controller's viewpoint using the Intel vendor-specific read/write latency log page.
    • Added namespace reservation command support, which can be used to coordinate sharing of a namespace between multiple hosts.
    • Added hardware SGL support, which enables use of scattered buffers that don't conform to the PRP list alignment and length requirements on supported NVMe controllers.
    • Added end-to-end data protection support, including the ability to write and read metadata in extended LBA (metadata appended to each block of data in the buffer) and separate metadata buffer modes. See spdk_nvme_ns_cmd_write_with_md() and spdk_nvme_ns_cmd_read_with_md() for details.
  • IOAT
    • The DMA block fill feature is now exposed via the ioat_submit_fill() function. This is functionally similar to memset(), except the memory is filled with an 8-byte repeating pattern instead of a single byte like memset.
  • PCI
    • Added support for using DPDK for PCI device mapping in addition to the existing libpciaccess option. Using the DPDK PCI support also allows use of the Linux VFIO driver model, which means that SPDK userspace drivers will work with the IOMMU enabled. Additionally, SPDK applications may be run as an unprivileged user with access restricted to a specific set of PCIe devices.
    • The PCI library API was made more generic to abstract away differences between the underlying PCI access implementations.

v1.2.0: IOAT user-space driver

This release adds a user-space driver with support for the Intel I/O Acceleration Technology (I/OAT, also known as "Crystal Beach") DMA offload engine.

  • IOAT
    • New user-space driver supporting DMA memory copy offload
    • Example programs ioat/perf and ioat/verify
    • Kernel-mode DMA engine test driver kperf for performance comparison
  • NVMe
    • Per-I/O flags for Force Unit Access (FUA) and Limited Retry
    • Public API for retrieving log pages
    • Reservation register/acquire/release/report command support
    • Scattered payload support - an alternate API to provide I/O buffers via a sequence of callbacks
    • Declarations and nvme/identify support for Intel SSD DC P3700 series vendor-specific log pages and features
  • Updated to support DPDK 2.2.0

v1.0.0: NVMe user-space driver

This is the initial open source release of the Storage Performance Development Kit (SPDK).


  • NVMe user-space driver
  • NVMe example programs
    • examples/nvme/perf tests performance (IOPS) using the NVMe user-space driver
    • examples/nvme/identify displays NVMe controller information in a human-readable format
  • Linux and FreeBSD support