SPDK I/O Acceleration

Overview

The SPDK is used to accelerate I/O flushing in Ceph all-flash storage and reduce I/O latency.

Technical Principles

Key technologies:

User space only: This feature moves all necessary drivers to the user space to slash system call overheads and implement zero copy.

Polling: For high-speed physical storage devices, the use of polling instead of interrupt notifications to determine request completion reduces latency and minimizes performance fluctuations.

Lock-free: No lock mechanism is used for synchronization on I/O paths to reduce latency and improve throughput.

Figure 1 Ceph I/O write process before the optimization

Figure 2 Ceph I/O write process after the optimization

Expected Results

The latency of a single Ceph 4 KB I/O is reduced from 600 μs to 400 μs.