fio: fio (Flexible I/O Tester) fio: fio: fio is an I/O tool meant to be used both for benchmark and fio: stress/hardware verification. It has support for 13 different types of fio: I/O engines (sync, mmap, libaio, posixaio, SG v3, splice, null, fio: network, syslet, guasi, solarisaio, and more), I/O priorities (for fio: newer Linux kernels), rate I/O, forked or threaded jobs, and much fio: more. It can work on block devices as well as files. fio displays all fio: sorts of I/O performance information. Fio is in wide use in many fio: places, for both benchmarking, QA, and verification purposes. fio: