Unnecessary data copy during cold snapshot
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
OpenStack Compute (nova) |
Expired
|
Medium
|
Unassigned |
Bug Description
When creating a cold snapshot, LibvirtDriver.
In case of snapshotting a local file backed VM to Swift, that's one copy too many: if the target format matches the source format, the local file can be uploaded directly, halving the time it takes to create a snapshot. In case of snapshotting an RBD backed VM to RBD backed Glance, that's two copies too many: a copy-on-write clone of the VM drive could obviate the need to copy any data at all.
I think that instead of passing the target location as a temporary file path under snapshots_
Changed in nova: | |
status: | Opinion → Confirmed |
Changed in nova: | |
importance: | Wishlist → Medium |
Changed in nova: | |
status: | Confirmed → Incomplete |
Personally, the VM could be turned on at any time, so this seems like the safest thing to do.
I will let the libvirt experts take a look at this.