On 25 August 2014 10:31, Wido den Hollander <wido at 42on.com> wrote: > On 08/24/2014 08:27 PM, Andrei Mikhailovsky wrote: >> >> Hello guys, >> >> I am planning to do rbd images off-site backup with rbd export-diff and I >> was wondering if ceph has checksumming functionality so that I can compare >> source and destination files for consistency? If so, how do I retrieve the >> checksum values from the ceph cluster? >> > > That would be rather difficult. There is no checksum, but to have a valid > checksum you would need to verify the whole RBD image. > > That means reading the whole image and calculating the checksum based on > that. > It could be done in a slightly better way I think, if you kept a cache of object checksums -> mtimes for the objects that make up the image and then only update the sums for the objects that have changed since the last diff. Still not ideal but at least saves re-reading objects that haven't changed at all.
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