fio使用

關於lat(I/O completion latency)、clat(complete latency)、slat(summit latency)：

lat is the total latency. slat is the time it takes to submit the
IO to the kernel, clat is the time from when slat is over and until the
device has completed it (and the application is notified). Hence lat is
slat + clat.

一、rw_sequencer

identical或者sequential

如rw=randread:8 這樣每8次io就更改一次offset。那麼這個rw_sequencer控制在這8次的io時的offset。

二、#!/usr/local/bin/fio  --debug=io

使用debug選項能夠看到它的io的詳細狀況

三、rw=randread:51200

表示每51200次io從新取offset

四、file_service_type=random:51200

表示每51200次io從新隨機取下一個文件