7:29 p.m.
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
9:58 a.m.
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
16:34:46.709Adding 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.xxxAdding 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_bg(a)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.
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
8:15 p.m.
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_bg(a)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_bg(a)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 <http://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 <mailto:root@engine> ~]# cat /sys/block/vda/queue/scheduler
[mq-deadline] kyber none
[root@engine <mailto: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
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participants (3)
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Darrell Budic -
Strahil -
Strahil Nikolov