Hi, have done the test again in a cleaner way. Same pool, same VM, different hosts (qemu 2.4 + qemu 2.2) but same hardware. But only one run!
The biggest difference is due cache settings: qemu2.4 cache=writethrough iops=3823 bw=15294KB/s qemu2.4 cache=writeback iops=8837 bw=35348KB/s qemu2.2 cache=writethrough iops=2996 bw=11988KB/s qemu2.2 cache=writeback iops=7980 bw=31921KB/s iothread does change anything, because only one disk is used. Test: io --time_based --name=benchmark --size=4G --filename=test.bin --ioengine=libaio --randrepeat=0 --iodepth=128 --direct=1 --invalidate=1 --verify=0 --verify_fatal=0 --numjobs=4 --rw=randwrite --blocksize=4k --group_reporting Udo On 22.11.2015 23:59, Udo Lembke wrote: > Hi Zoltan, > you are right ( but this was two running systems...). > > I see also an big failure: "--filename=/mnt/test.bin" (use simply > copy/paste without to much thinking :-( ) > The root filesystem is not on ceph (on both servers). > So my measurements are not valid!! > > I would do the measurements clean tomorow. > > > Udo > > > On 22.11.2015 14:29, Zoltan Arnold Nagy wrote: >> It would have been more interesting if you had tweaked only one >> option as now we can’t be sure which changed had what impact… :-) >>
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