On Wed, Jan 7, 2015 at 9:55 PM, Christian Balzer <chibi@xxxxxxx> wrote: > On Wed, 7 Jan 2015 17:07:46 -0800 Craig Lewis wrote: > >> On Mon, Dec 29, 2014 at 4:49 PM, Alexandre Oliva <oliva@xxxxxxx> wrote: >> >> > However, I suspect that temporarily setting min size to a lower number >> > could be enough for the PGs to recover. If "ceph osd pool <pool> set >> > min_size 1" doesn't get the PGs going, I suppose restarting at least >> > one of the OSDs involved in the recovery, so that they PG undergoes >> > peering again, would get you going again. >> > >> >> It depends on how incomplete your incomplete PGs are. >> >> min_size is defined as "Sets the minimum number of replicas required for >> I/O.". By default, size is 3 and min_size is 2 on recent versions of >> ceph. >> >> If the number of replicas you have drops below min_size, then Ceph will >> mark the PG as incomplete. As long as you have one copy of the PG, you >> can recover by lowering the min_size to the number of copies you do >> have, then restoring the original value after recovery is complete. I >> did this last week when I deleted the wrong PGs as part of a toofull >> experiment. >> > Which of course begs the question of why not having min_size at 1 > permanently, so that in the (hopefully rare) case of loosing 2 OSDs at the > same time your cluster still keeps working (as it should with a size of 3). You no longer have write durability if you only have one copy of a PG. Sam is fixing things up so that recovery will work properly as long as you have a whole copy of the PG, which should make things behave as people expect. -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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