Hi, On Fri, 17 May 2019 at 16:20, Manu K.S. <cse.manuks@xxxxxxxxx> wrote: > > Hi, what will be the iodepth for each job with below 3 commands? > > COMMAND 1 > ----------------- > fio --name=fiotest --filename=/dev/sdb --rw=read --numjobs=1 > --iodepth=4 --size=1G --bs=4k --runtime=120 --time_based > > COMMAND 2 > ------------------- > fio --name=fiotest --filename=/dev/sdb --rw=read --numjobs=2 > --iodepth=4 --size=1G --bs=4k --runtime=120 --time_based > > COMMAND 3 > ------------------- > fio --name=fiotest --filename=/dev/sdb:/dev/sdc --rw=read --numjobs=2 > --iodepth=4 --size=1G --bs=4k --runtime=120 --time_based Hard to say without more context but assuming you're on Linux: COMMAND 1 You're going to get a depth of 1 because the default ioengine chosen when you don't specify one on Linux is synchronous (see the iodepth description in the fio help for warnings about depth and synchronous ioengines - https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-iodepth ). Maybe you wanted to use libaio with direct=1 (see the libaio section in https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-ioengine for more details)? COMMAND 2 I'd guess you will get an overall depth of 2 (1 per job). COMMAND 3 I'd guess you will get an overall depth of 2 (1 per job). Multiple files in filename won't impact the depth only which file each I/O goes to (which is roundrobin by default - https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-file-service-type ). NB: fio will try and report the depths it is achieving see the "IO depths" output in the example on https://fio.readthedocs.io/en/latest/fio_doc.html#interpreting-the-output . What your disk actually sees can be different though depending on what the kernel chooses to do with the submitted I/O. -- Sitsofe | http://sucs.org/~sits/
