On Fri, Apr 24, 2020 at 6:16 AM Damien Le Moal <Damien.LeMoal@xxxxxxx> wrote: > > On 2020/04/24 12:11, Damien Le Moal wrote: > > On 2020/04/23 23:41, Seena Fallah wrote: > >> Hi all. > >> > >> I'm trying to probe my file system with fio. I don't want to benchmark > >> my file system. The only thing I want do is to for example write 100K > >> file on a file system and then check how much IO does it take to write > >> and the bandwidth and the runtime. > >> The main thing I want is to just write that file size and don't bench on that. > >> Can anyone help me which ioengine or which args should I use to do this probe? > >> > >> Thanks. > >> > > > > dd if=/dev/zero of=/path/to/your/file/to/write bs=100K count=i conv=fsync > > > > Oops... Should be: > > dd if=/dev/zero of=/path/to/your/file/to/write bs=100K count=1 conv=fsync > > obviously for 100K :) > > You will get the write bandwidth with this. For knowing how many IOs this take, > you will need to trace the kernel IO stack (blktrace). No way to know this > exactly from user space, that is, if by "IO" you mean "storage device commands". > If by "IO" you mean "system calls", then with the above command, it will be > exactly 1 "write()" call (use strace to see it). > > -- > Damien Le Moal > Western Digital Research Yeah, fio might not be the best tool for this purpose. As Damien said - 'dd' is a good alternative. You could also use the xfs_io tool. It's not really xfs related, it's a general i/o and filesystem operations tool. It's part of the xfsprogs package and most likely already installed on your host. Here's an example: xfs_io -c "pwrite 0 100" -f /path/to/file Writes 100 bytes at offset 0 to the file. It will give you some timing info and bandwidth stats. Yigal
