Thanks Greg. Can I just confirm, does it do a full backfill automatically in the case where the log no longer overlaps? I guess the key question is - do I have to worry about it, or will it always "do the right thing"? Tim. On Fri, Feb 21, 2014 at 11:57:09AM -0800, Gregory Farnum wrote: > It depends on how long ago (in terms of data writes) it disappeared. > Each PG has a log of the changes that have been made (by default I > think it's 3000? Maybe just 1k), and if an OSD goes away and comes > back while the logs still overlap it will just sync up the changed > objects. Otherwise it has to do a full backfill across the PG. > -Greg > Software Engineer #42 @ http://inktank.com | http://ceph.com > > On Fri, Feb 21, 2014 at 10:33 AM, Tim Bishop <tim-lists@xxxxxxxxxxx> wrote: > > I'm wondering how Ceph deals with OSDs that have been away for a while. > > Do they need to be completely rebuilt, or does it know which objects are > > good and which need to go? > > > > I know Ceph handles well the situation of an OSD going away, and > > rebalances etc to maintain the required redundancy levels. But I'm > > unsure what it does when an OSD comes back some time later still > > containing data. > > > > Tim. -- Tim Bishop http://www.bishnet.net/tim/ PGP Key: 0x6C226B37FDF38D55 _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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