Hi Darrel, Still, based on my experience we shouldn't queue our I/O in the VM, just to do the same in the Host.
I'm still considering if I should keep deadline in my hosts or to switch to 'cfq'. After all, I'm using Hyper-converged oVirt and this needs testing. What I/O scheduler are you using on the host? Best Regards, Strahil NikolovOn Mar 18, 2019 19:15, Darrell Budic <bu...@onholyground.com> wrote: > > Checked this on mine, see the same thing. Switching the engine to noop > definitely feels more responsive. > > I checked on some VMs as well, it looks like virtio drives (vda, vdb….) get > mq-deadline by default, but virtscsi gets noop. I used to think the tuned > profile for virtual-guest would set noop, but apparently not… > > -Darrell > >> On Mar 18, 2019, at 1:58 AM, Strahil Nikolov <hunter86...@yahoo.com> wrote: >> >> Hi All, >> >> I have changed my I/O scheduler to none and here are the results so far: >> >> Before (mq-deadline): >> Adding a disk to VM (initial creation) START: 2019-03-17 16:34:46.709 >> Adding a disk to VM (initial creation) COMPLETED: 2019-03-17 16:45:17.996 >> >> After (none): >> Adding a disk to VM (initial creation) START: 2019-03-18 08:52:02.xxx >> Adding a disk to VM (initial creation) COMPLETED: 2019-03-18 08:52:20.xxx >> >> Of course the results are inconclusive, as I have tested only once - but I >> feel the engine more responsive. >> >> Best Regards, >> Strahil Nikolov >> >> В неделя, 17 март 2019 г., 18:30:23 ч. Гринуич+2, Strahil >> <hunter86...@yahoo.com> написа: >> >> >> Dear All, >> >> I have just noticed that my Hosted Engine has a strange I/O scheduler: >> >> Last login: Sun Mar 17 18:14:26 2019 from 192.168.1.43 >> [root@engine ~]# cat /sys/block/vda/queue/scheduler >> [mq-deadline] kyber none >> [root@engine ~]# >> >> Based on my experience anything than noop/none is useless and performance >> degrading for a VM. >> >> Is there any reason that we have this scheduler ? >> It is quite pointless to process (and delay) the I/O in the VM and then >> process (and again delay) on Host Level . >> >> If there is no reason to keep the deadline, I will open a bug about it. >> >> Best Regards, >> Strahil Nikolov >> >> Dear All, >> >> I have just noticed that my Hosted Engine has a strange I/O scheduler: >> >> Last login: Sun Mar 17 18:14:26 2019 from 192.168.1.43 >> [root@engine ~]# cat /sys/block/vda/queue/scheduler >> [mq-deadline] kyber none >> [root@engine ~]# >> >> Based on my experience anything than noop/none is useless and performance >> degrading for a VM. >> >>
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