I removed some osds from a host yesterday using the reweight method and it worked well. There was only one rebalance and then I could perform the rest of the documented removal steps immediately with no further recovery. I reweighted to 0.0.
Shinobu, can you explain why you have found 0.2 is better than 0.0? What happens when you use 0.2 and what happens when you use 0.0 ? Rafael On 12 January 2016 at 09:13, Shinobu Kinjo <ski...@redhat.com> wrote: > Based on my research, 0.2 is better than 0.0. > Probably it depends though. > > > ceph osd crush reweight osd.X 0.0 > > Rgds, > Shinobu > > ----- Original Message ----- > From: "Andy Allan" <gravityst...@gmail.com> > To: "Rafael Lopez" <rafael.lo...@monash.edu> > Cc: ceph-users@lists.ceph.com > Sent: Monday, January 11, 2016 8:08:38 PM > Subject: Re: [ceph-users] double rebalance when removing osd > > On 11 January 2016 at 02:10, Rafael Lopez <rafael.lo...@monash.edu> wrote: > > > @Steve, even when you remove due to failing, have you noticed that the > cluster rebalances twice using the documented steps? You may not if you > don't wait for the initial recovery after 'ceph osd out'. If you do 'ceph > osd out' and immediately 'ceph osd crush remove', RH support has told me > that this effectively 'cancels' the original move triggered from 'ceph osd > out' and starts permanently remapping... which still doesn't really explain > why we have to do the ceph osd out in the first place.. > > This topic was last discussed in December - the documentation for > removing an OSD from the cluster is not helpful. Unfortunately it > doesn't look like anyone is going to fix the documentation. > > http://comments.gmane.org/gmane.comp.file-systems.ceph.user/25627 > > Basically, when you want to remove an OSD, there's an alternative > sequence of commands that avoids the double-rebalance. > > The better approach is to reweight the OSD to zero first, then wait > for the (one and only) rebalance, then mark out and remove. Here's > more details from the previous thread: > > http://permalink.gmane.org/gmane.comp.file-systems.ceph.user/25629 > > Thanks, > Andy > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Senior Storage Engineer - Automation and Delivery Infrastructure Services - eSolutions 738 Blackburn Rd, Clayton Monash University 3800 Telephone: +61 3 9905 9118 <%2B61%203%209905%9118> Mobile: +61 4 27 682 670 Email rafael.lo...@monash.edu
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