On 01/02/2014 10:51 PM, James Harper wrote:
I've not used ceph snapshots before. The documentation says that the rbd device should not be in use before creating a snapshot. Does this mean that creating a snapshot is not an atomic operation? I'm happy with a crash consistent filesystem if that's all the warning is about.
It's atomic, the warning is just that it's crash consistent, not application-level consistent.
If it is atomic, can you create multiple snapshots as an atomic operation? The use case for this would be a database spread across multiple volumes, eg database on one rbd, logfiles on another.
No, but now that you mention it this would be technically pretty simple to implement. If multiple rbds referred to the same place to get their snapshot context, they could all be snapshotted atomically. Josh _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
