On 11/23/2012 05:59 AM, Sage Weil wrote:
On Thu, 22 Nov 2012, Stefan Priebe - Profihost AG wrote:
Hello list,
right now a rbd export exports exactly the size of the disk even if there is
KNOWN free space. Is this inteded to change?
Might it be possible to export just differences between snapshots and merge
them later?
We were just talking about this the other day.
Step 1 is to create a mechanism to output a list of block ranges that
have/have not changed between snapshots.
Step 2 is to export the incremental changes. The hangup there is figuring
out a generic and portable file format to represent those incremental
changes; we'd rather not invent something ourselves that is ceph-specific.
Suggestions welcome!
I'm not sure about the licensing and such, but doesn't VMware do
something with their VMDK images?
There you have a base image and each snapshot is a separate file.
You have:
image.vmdk
image-delta1.vmdk
image-delta2.vmdk
..
..
You can merge all these files together again to a new image based on the
last snapshot you feeded it.
They probably didn't use a open format to do this, but something in that
direction is what you are looking for?
Wido
sage
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