fio

fio (flexible I/O tester) simulates a given I/O workload on storage devices and file systems, to measure performance or to find and reproduce bugs. It was written by Jens Axboe to avoid writing a specific test program for each workload.

A job file describes the workload: number of processes or threads, read and write patterns (sequential or random), block sizes, I/O depth, I/O engine (such as libaio, io_uring or memory-mapped I/O), duration and data verification. fio then reports bandwidth, IOPS and latency statistics. Long or intensive jobs are used to stress disks and storage systems and check data integrity under load.

fio runs on Linux, Windows, macOS and other systems. It is free and open source under the GPL-2.0 licence.