-----Original Message----- From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Xavier Trilla Sent: Tuesday, October 21, 2014 12:42 AM To: ceph-users@xxxxxxxxxxxxxx Subject: RADOS pool snaps and RBD Hi, It seems Ceph doesn't allow rados pool snapshots on RBD pools which have or had RBD snapshots. They only work on RBD pools which never had a RBD snapshot. So, basically this works: rados mkpool test-pool 1024 1024 replicated rbd -p test-pool create --size=102400 test-image ceph osd pool mksnap test-pool rados-snap But this doesn't: rados mkpool test-pool 1024 1024 replicated rbd -p test-pool create --size=102400 test-image rbd -p test-pool snap create test-image@rbd-snap ceph osd pool mksnap test-pool rados-snap And we get the following error message: Error EINVAL: pool test-pool is in unmanaged snaps mode I've been checking the source code and it seems to be the expecte behavior, but I did not manage to find any information regarding "unmanaged snaps mode". Also I did not find any information about RBD snapshots and pool snapshots being mutually exclusive. And even deleting all the RBD snapshots in a pool doesn't enable RADOS snapshots again. So, I have a couple of questions: - Are RBD and RADOS snapshots mutually exclusive? >>>> I think the answer is yes , this will be checked before you get your snap_seq in OSDMonitor. - What does mean "unmanaged snaps mode" message? >>>> This means you have create a rbd snapshot , you cannot create a snapshot for rados - Is there any way to revert a pool status to allow RADOS pool snapshots after all RBD snapshots are removed? >>>> not very sure We are designing a quite interesting way to perform incremental backups of RBD pools managed by OpenStack Cinder. The idea is to do the incremental backup at a RADOS level, basically using the mtime property of the object and comparing it against the time we did the last backup / pool snapshot. That way it should be really easy to find modified objects transferring only them, making the implementation of a DR solution easier.. But the issue explained here would be a big problem, as the backup solution would stop working if just one user creates a RBD snapshot on the pool (For example using Cinder Backup). I hope somebody could give us more information about this "unmanaged snaps mode" or point us to a way to revert this behavior once all RBD snapshots have been removed from a pool. Thanks! Saludos cordiales, Xavier Trilla P. Silicon Hosting ¿Sabías que ahora en SiliconHosting resolvemos tus dudas técnicas gratis? Más información en: siliconhosting.com/qa/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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