fio 是一个 I/O 工具用来对硬件进行压力测试和验证，支持13种不同的I/O引擎，包括：sync, mmap, libaio, posixaio, SG v3, splice, null, network, syslet, guasi, solarisaio 等等, I/O priorities (for newer Linux kernels), rate I/O, forked or threaded jobs, 等等。
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. Fio is in wide use in many places, for both benchmarking, QA, and verification purposes. It supports Linux, FreeBSD, NetBSD, OS X, OpenSolaris, AIX, and Windows.
