[Gluster-users] Horrible Gluster Performance

Philip flips01 at googlemail.com
Fri Apr 13 10:06:23 UTC 2012


Am 13. April 2012 11:42 schrieb Brian Candler <B.Candler at pobox.com>:

> On Fri, Apr 13, 2012 at 11:25:58AM +0200, Philip wrote:
> >    Sometimes the io-latency skyrockets and there is no
> >    access possible on the raid for >10 seconds.
>
> Have you checked
> http://community.gluster.org/a/linux-kernel-tuning-for-glusterfs/
> ?
>
> If you have a large amount of RAM and a lot of writes, maybe you're
> accumulating large amounts of dirty data which is then being synchronously
> flushed.
>

I indeed have lots of ram but I've disabled all write access for a few
hours to check if this issue is write related. These latency spikes did
also happen when there were no writes at all.

I haven't changed these values. They were at
vm.dirty_background_ratio = 10
vm.dirty_ratio = 20

I've changed it to
vm.dirty_background_ratio = 2
vm.dirty_ratio = 10
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