Re: RADOS + deep scrubbing performance issues in production environment

[Filippos Giannakos <philipgian@grnet.gr>]

On Tue, Jan 28, 2014 at 01:30:46AM -0500, Mike Dawson wrote:
> 
> On 1/27/2014 1:45 PM, Sage Weil wrote:
> >There is also
> >
> >  ceph osd set noscrub
> >
> >and then later
> >
> >  ceph osd unset noscrub
> >
> In my experience scrub isn't nearly as much of a problem as
> deep-scrub. On a IOPS constrained cluster with writes approaching
> the available aggregate spindle performance minus replication
> penalty and possibly co-located osd journal penalty, scrub may run
> without any disruption. But deep-scrub tends to make iowait on the
> spindles get ugly.
> 
> To disable/enable deep-scrub use:
> 
> ceph osd set nodeep-scrub
> ceph osd unset nodeep-scrub
>

Yes, deep-scrubbing is much worse than scrubbing, but I think fully disabling it
is not a good option. But having days of degraded performance isn't either.
That's why I am bringing up the problem and seeking for a solid solution
regarding the matter.

Kind Regards,
-- 
Filippos
<philipgian@grnet.gr>