libvirt: Use live blockcommit for snapshot deletion

Registered by Eric Harney

Nova uses libvirt to perform deletion/merging of volume snapshots for some Cinder drivers. Currently it uses blockRebase for this when deleting the oldest snapshot and blockCommit otherwise. Newer versions of libvirt (1.2.7+) can use blockCommit for the oldest snapshot as well, which is far more efficient. Nova should use this when libvirt supports it.

Blueprint information

Status:
Not started
Approver:
John Garbutt
Priority:
Low
Drafter:
Eric Harney
Direction:
Needs approval
Assignee:
Eric Harney
Definition:
Pending Approval
Series goal:
Accepted for trunk
Implementation:
Not started
Milestone target:
milestone icon next

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Sprints

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My assumption is that this is a narrow enough change to not need a nova spec. - eharney

OK, yeah, I think that makes sense. --johnthetubaguy

Bumping to k-2 -- mikal 9 Dec 2014

This has missed the Feature Freeze Proposal deadline, unapproving this blueprint. --johnthetubaguy 26th Jan 2015

(?)

Work Items

Work items:
Patch libvirt _volume_snapshot_delete to use the blockCommit path rather than blockRebase when possible. : TODO

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