hi! I've also noticed that behavior and have submitted a patch some time ago that should fix (2): https://github.com/ceph/ceph/pull/27288
But it may well be that there's more cases where PGs are not discovered on devices that do have them. Just recently a lot of my data was degraded and then recreated even though it would have been available on a node that had taken very long to reboot. What you can do also is to mark your OSD in and then out right away, the data is discovered then. Although with my patch that shouldn't be necessary any more. Hope this helps you. Cheers -- Jonas On 22/12/2019 19.48, Oliver Freyermuth wrote: > Dear Cephers, > > I realized the following behaviour only recently: > > 1. Marking an OSD "out" sets the weight to zero and allows to migrate data > away (as long as it is up), > i.e. it is still considered as a "source" and nothing goes to degraded > state (so far, everything expected). > 2. Restarting an "out" OSD, however, means it will come back with "0 pgs", > and if data was not fully migrated away yet, > it means the PGs which were still kept on it before will enter degraded > state since they now lack a copy / shard. > > Is (2) expected? > > If so, my understanding that taking an OSD "out" to let the data be migrated > away without losing any redundancy is wrong, > since redundancy will be lost as soon as the "out" OSD is restarted (e.g. due > to a crash, node reboot,...) and the only safe options would be: > 1. Disable the automatic balancer. > 2. Either adjust the weights of the OSDs to drain to zero, or use pg upmap to > drain them. > 3. Reenable the automatic balancer only after having fully drained those OSDs > and performing the necessary intervention > (in our case, recreating the OSDs with a faster blockdb). > > Is this correct? > > Cheers, > Oliver > > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
