These are the commands : Command 1: fio --filename=/dev/sdb --time_based --rw=read --name=fiotest --prio=0 --bs=4k --direct=1 --ioengine=libaio --runtime=60 --numjobs=2 --iodepth=4 Command 2: fio --filename=/dev/sdb:/dev/sdc --time_based --rw=read --name=fiotest --prio=0 --bs=4k --direct=1 --ioengine=libaio --runtime=60 --numjobs=2 --iodepth=4 For command 1, what is the logic used ? If I'm specifying numjobs=2 & iodepth=4, will each job get 2 IO depth, or does it mean each job will be running with IO depth 4? This is a bit confusing for me. For command 2, will each disk have : 1. 2 jobs per disk with 4 IO depth for each job? 2. 2 jobs per disk with 2 IO depth for each job? 2. One job per disk with 2 IO depth for each job? 3. One job per disk with 4 IO depth? -- Cheers Manu K S On Sat, May 18, 2019 at 5:02 PM Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: > > Hi, > > I'm going to stop here for now because the command line you posted > earlier is missing something if you are really using libaio so I'm > getting confused (maybe you are saying you are using a new command > line but you forgot to post it in your new email?). I'm afraid we need > to see the full current command line (and the contents of any job > files) to be able to answer questions like this - see > https://github.com/axboe/fio/blob/master/REPORTING-BUGS for the type > of information that is required. Could you follow up with ALL the > information requested there? To maximize the odds of getting to a > resolution ensure you include the fio output as mentioned in > REPORTING-BUGS - don't be tempted to skip sending it to us in this > case! > > On Sat, 18 May 2019 at 09:43, Manu K.S. <cse.manuks@xxxxxxxxx> wrote: > > > > Thank you for the information. > > Yes I'm indeed using libaio as the ioengine on a linux server. > > > > For command 2, what is the logic? If I'm specifying numjobs=2 & > > iodepth=4 will each job get 2 IO depth, or does it mean each job will > > be running with IO depth 4? This is a bit confusing for me. > > > > For command 3, will each disk have : > > 1. 2 jobs per disk with 4 IO depth for each job? > > 2. 2 jobs per disk with 2 IO depth for each job? > > 2. One job per disk with 2 IO depth for each job? > > 3. One job per disk with 4 IO depth? > > > > > > -- > > Cheers > > Manu K S > > > > On Sat, May 18, 2019 at 12:43 PM Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: > > > > > > 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/
