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 dilla...@redhat.com http://www.redhat.com
- Original Message - From: Steve Anthony sma...@lehigh.edu
To: ceph-users@lists.ceph.com Sent: Tuesday, March 3, 2015 2:06:44 PM
Subject: [ceph-users] 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
sma...@lehigh.edu ___
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--
Steve Anthony
LTS HPC Support Specialist
Lehigh University
sma...@lehigh.edu
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