From mboxrd@z Thu Jan 1 00:00:00 1970 From: Filippos Giannakos Subject: Re: RADOS + deep scrubbing performance issues in production environment Date: Tue, 28 Jan 2014 20:13:25 +0200 Message-ID: <20140128181325.GD11532@philipgian-mac> References: <20140127151321.GD26390@philipgian-mac> <52E74E96.8070202@cloudapt.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from averel.grnet-hq.admin.grnet.gr ([195.251.29.3]:29373 "EHLO averel.grnet-hq.admin.grnet.gr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755205AbaA1SN3 (ORCPT ); Tue, 28 Jan 2014 13:13:29 -0500 Content-Disposition: inline In-Reply-To: <52E74E96.8070202@cloudapt.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Mike Dawson Cc: Sage Weil , Kyle Bader , "ceph-devel@vger.kernel.org" , synnefo-devel@googlegroups.com 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