On 1/3/14, 3:21 AM, "Josh Durgin" <josh.durgin@xxxxxxxxxxx> wrote: >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 >_______________________________________________ I had been trying to imagine a use for pool-level snapshotting after I¹d read about that feature. Thanks for settling that! JL _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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