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/
