SPDK

SPDK, or Storage Performance Development Kit, is an open-source software framework designed to help developers build high-performance, scalable storage applications. It aims to minimize latency and maximize throughput by moving storage processing into user space and bypassing the traditional kernel I/O stack.

The framework achieves this through a set of libraries and user-space drivers that operate directly with PCIe NVMe devices using poll-based event loops. It relies on mechanisms such as huge pages and VFIO/UIO to map device memory into user space and employs a reactor-style model to issue asynchronous I/O, enabling high levels of parallelism and low overhead.

SPDK provides a range of components and abstractions, including block devices (bdev) that virtualize storage, and support for NVMe and NVMe over Fabrics (NVMf) targets and initiators. It also includes blob storage facilities like BlobFS and virtualization support through vhost for presenting storage to virtual machines. A JSON-RPC interface and accompanying tooling enable runtime configuration and monitoring, allowing applications to manage and optimize I/O paths without kernel involvement.

Applications and environments that require extreme storage performance—such as high-speed databases, storage arrays, and virtualization platforms—benefit from SPDK. It is used to build custom, low-latency I/O paths, optimize NVMe device utilization, and enable efficient NVMe-oF deployments in performance-focused deployments.

SPDK originated as an Intel project and has evolved into an open-source, community-driven effort. It is primarily written in C and designed to be extensible, allowing developers to build specialized storage solutions and integrate them into broader systems.