Hi Indra, Le 04/05/2014 06:11, Indra Pramana a ?crit : > Would like to share after I tried yesterday, this doesn't work: > > > - ceph osd set noout > > - sudo stop ceph-osd id=12 > > - Replace the drive, and once done: > > - sudo start ceph-osd id=12 You said a few lines afterwards that a new OSD number is assigned, so there is a typo here : you would use "sudo start ceph-osd id=new_id" (13 for example). I don't know how you could start the new OSD with the number of the old one ? (except if you removed it before, please clarify) > > - ceph osd unset noout > > Once drive replaced, we need to ceph-deploy zap and prepare the new > drive, and a new osd number will be assigned. Remapping will start > immediately after the new OSD is in the cluster. I am not a guru, but I think this is an expected behaviour : noout only prevents OSDs to go out, here a new one in added to the cluster so a remapping begins. A thing that come in my mind is that, at the moment of the remapping, you still have the old OSD marked IN+DOWN, so the remapping is maybe computed with all the OSD marked IN, and a new remapping is computed right after you remove the old OSD. Maybe noin and nobackfill flags could plays well here in order to *freeze* every actions related to OSD topology changes until everything has been done, so I would try : - set noout + noin and/or nobackfill (maybe noin would suffice, not that the cluster is naked at this time ...) - stop old OSD - remove old OSD - add new OSD - unset flags Cheers > Then we can safely remove the old OSD and unset noout, and wait for > recovery completed. > > However, the "set noout" in the first place indeed helped to prevent > remapping to take place when we stop the OSD and replace the drive. So > it's advisable to use this feature when replacing drive -- unless if > the drive is already failed and the OSD is already down in the first > place. > > Thank you. > > > > On Sat, May 3, 2014 at 5:51 PM, Andrey Korolyov <andrey at xdel.ru > <mailto:andrey at xdel.ru>> wrote: > > On Sat, May 3, 2014 at 4:01 AM, Indra Pramana <indra at sg.or.id > <mailto:indra at sg.or.id>> wrote: > > Sorry forgot to cc the list. > > > > On 3 May 2014 08:00, "Indra Pramana" <indra at sg.or.id > <mailto:indra at sg.or.id>> wrote: > >> > >> Hi Andrey, > >> > >> I actually wanted to try this (instead of remove and readd OSD) > to avoid > >> remapping of PGs to other OSDs and the unnecessary I/O load. > >> > >> Are you saying that doing this will also trigger remapping? I > thought it > >> will just do recovery to replace missing PGs as a result of the > drive > >> replacement? > >> > >> Thank you. > >> > > Yes, remapping will take place, though it is a bit counterintuitive > and I suspect that the roots are the same as with double data > placement recalculation with out + rm procedure. Actually Inktank > people may answer the question with more details I suppose. Also I > think that preserving of the collections may eliminate remap during > such kind of refill, though it is not trivial thing to do and I had > not experimented with this. > > >> On 2 May 2014 21:02, "Andrey Korolyov" <andrey at xdel.ru > <mailto:andrey at xdel.ru>> wrote: > >>> > >>> On 05/02/2014 03:27 PM, Indra Pramana wrote: > >>> > Hi, > >>> > > >>> > May I know if it's possible to replace an OSD drive without > removing / > >>> > re-adding back the OSD? I want to avoid the time and the > excessive I/O > >>> > load which will happen during the recovery process at the > time when: > >>> > > >>> > - the OSD is removed; and > >>> > - the OSD is being put back into the cluster. > >>> > > >>> > I read David Zafman's comment on this thread, that we can > set "noout", > >>> > take OSD "down", replace the drive, and then bring the OSD > back "up" > >>> > and > >>> > unset "noout". > >>> > > >>> > http://www.spinics.net/lists/ceph-users/msg05959.html > >>> > > >>> > May I know if it's possible to do this? > >>> > > >>> > - ceph osd set noout > >>> > - sudo stop ceph-osd id=12 > >>> > - Replace the drive, and once done: > >>> > - sudo start ceph-osd id=12 > >>> > - ceph osd unset noout > >>> > > >>> > The cluster was built using ceph-deploy, can we just replace > a drive > >>> > like that without zapping and preparing the disk using > ceph-deploy? > >>> > > >>> > >>> There will be absolutely no quirks except continuous remapping > with > >>> peering along entire recovery process. If your cluster may > meet this > >>> well, there is absolutely no problem to go through this flow. > Otherwise, > >>> in longer out+in flow, there are only two short intensive > recalculations > >>> which can be done at the scheduled time, comparing with > peering during > >>> remap, which can introduce unnecessary I/O spikes. > >>> > >>> > Looking forward to your reply, thank you. > >>> > > >>> > Cheers. > >>> > > >>> > > >>> > _______________________________________________ > >>> > ceph-users mailing list > >>> > ceph-users at lists.ceph.com <mailto:ceph-users at lists.ceph.com> > >>> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >>> > > >>> > > > > > > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- C?dric -------------- next part -------------- An HTML attachment was scrubbed... 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