fio is an I/O tool meant to be used both for benchmark and stress/hardware
verification. It has support for 4 different types of I/O engines (sync,
mmap, libaio, posixaio), I/O priorities (for newer Linux kernels), rate I/O,
forked or threaded jobs, and much more. It can work on block devices as
well as files. fio accepts job descriptions in a simple-to-understand text
format. Several example job files are included. fio displays all sorts of
I/O performance information, such as completion and submission latencies
(avg/mean/deviation), bandwidth stats, cpu and disk utilization, and more.