Jason, Ah, ok that makes sense. I was forgetting snapshots are read-only. Thanks! My plan was to do something like this. First, create a sync snapshot and seed the backup: rbd snap create rbd/small@sync rbd export rbd/small@sync ./foo rbd import ./foo backup/small rbd snap create backup/small@sync Then each day, create a daily snap on the backup cluster: rbd snap create backup/small@2015-02-03 Then send that day's changes: rbd export-diff --from-snap sync rbd/small ./foo.diff rbd import-diff ./foo.diff rbd/small Then remove and recreate the daily snap marker to prepare for the next sync. rbd snap rm rbd/small@sync rbd snap rm backup/small@sync rbd snap create rbd/small@sync rbd snap create backup/small@sync Finally remove any dated snapshots on the remote cluster outside the retention window. -Steve On 03/03/2015 04:37 PM, Jason Dillaman wrote: > Snapshots are read-only, so all changes to the image can only be applied to the HEAD revision. > > In general, you should take a snapshot prior to export / export-diff to ensure consistent images: > > rbd snap create rbd/small@snap1 > rbd export rbd/small@snap1 ./foo > > rbd import ./foo backup/small > rbd snap create backup/small@snap1 > > ** rbd/small and backup/small are now consistent through snap1 -- rbd/small might have been modified post snapshot > > rbd snap create rbd/small@snap2 > rbd export-diff --from-snap snap1 rbd/small@snap2 ./foo.diff > rbd import-diff ./foo.diff backup/small > > ** rbd/small and backup/small are now consistent through snap2. import-diff automatically created backup/small@snap2 after importing all changes. > > -- Jason Dillaman Red Hat dillaman@xxxxxxxxxx http://www.redhat.com > ----- Original Message ----- From: "Steve Anthony" <sma310@xxxxxxxxxx> > To: ceph-users@xxxxxxxxxxxxxx Sent: Tuesday, March 3, 2015 2:06:44 PM > Subject: import-diff requires snapshot exists? Hello, > I've been playing with backing up images from my production site > (running 0.87) to my backup site (running 0.87.1) using export/import > and export-diff/import-diff. After initially exporting and importing > the image (rbd/small to backup/small) I took a snapshot (called test1) > on the production cluster, ran export-diff from that snapshot, and > then attempted to import-diff the diff file on the backup cluster. # > rbd import-diff ./foo.diff backup/small start snapshot 'test1' does > not exist in the image, aborting Importing image diff: 0% > complete...failed. rbd: import-diff failed: (22) Invalid argument This > works fine if I create a test1 snapshot on the backup cluster before > running import-diff. However, it appears that the changes get written > into backup/small not backup/small@test1. So unless I'm not > understanding something, it seems like the content of the snapshot on > the backup cluster is of no importance, which makes me wonder why it > must exist at all. Any thoughts? Thanks! -Steve > -- Steve Anthony LTS HPC Support Specialist Lehigh University > sma310@xxxxxxxxxx _______________________________________________ > ceph-users mailing list ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- Steve Anthony LTS HPC Support Specialist Lehigh University sma310@xxxxxxxxxx
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