Storage interfaces have evolved more in the past 3 years than in the previous 20 years. In Linux, we see this happening at two different layers: (i) the user- / kernel-space I/O interface, where io_uring is bringing a low-weight, scalable I/O path; and (ii) and the host/device protocol interface, where key-values and zoned block devices are starting to emerge. Applications that want to leverage these new interfaces have to at least change their storage backends.

Almost 10 years ago, the SPDK userspace polled mode nvme driver showed performance and efficiency far surpassing what was capable with the Linux kernel. But in recent years, Linux has responded with io_uring and asynchronous NVMe passthrough interfaces. The xNVMe project has also helped storage projects and applications adapt to the ever-growing list of Linux storage interfaces. This talk will compare the strengths of the SPDK and Linux NVMe drivers, explain how xNVMe has enabled io_uring NVMe passthrough in SPDK, and share some early performance results.