The Storage Performance Development Kit (SPDK) provides a set of tools and libraries for writing high performance, scalable, user-mode storage applications. It achieves high performance through the use of a number of key techniques:

  • Moving all of the necessary drivers into userspace, which avoids syscalls and enables zero-copy access from the application.
  • Polling hardware for completions instead of relying on interrupts, which lowers both total latency and latency variance.
  • Avoiding all locks in the I/O path, instead relying on message passing.

The bedrock of SPDK is a user space, polled-mode, asynchronous, lockless NVMe driver. This provides zero-copy, highly parallel access directly to an SSD from a user space application. The driver is written as a C library with a single public header.

SPDK further provides a full block stack as a user space library that performs many of the same operations as a block stack in an operating system. This includes unifying the interface between disparate storage devices, queueing to handle conditions such as out of memory or I/O hangs, and logical volume management.

Finally, SPDK provides NVMe-oF, iSCSI, and vhost servers built on top of these components that are capable of serving disks over the network or to other processes. The standard Linux kernel initiators for NVMe-oF and iSCSI interoperate with these targets, as well as QEMU with vhost. These servers can be up to an order of magnitude more CPU efficient than other implementations. These targets can be used as examples of how to implement a high performance storage target, or used as the basis for production deployments.

20.01 SPDK NVMe-oF TCP Performance Report

May 6, 2020 • Karol Latecki

New performance report for SPDK NVMe-oF TCP has been published.


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

Apr 30, 2020 • Tomasz Zawadzki

On behalf of the SPDK community I’m pleased to announce the release of SPDK 20.04!


New spdk_top application

Apr 27, 2020 • Maciej Szwed

A new application has just joined SPDK family - spdk_top. Designed to resemble standard top, spdk_top provides additional insight into SPDK cores, lightweight threads, and pollers. Have you ever wondered which core is used most by your SPDK instance? Are you building your own bdev or library and want to know if your code is running efficiently? Are your new pollers busy most of the time? You can check that now with spdk_top and tune your implementation with the provided information to get even more from SPDK!