Use a linked-clone image as snapshot image to improve original snapshot

Registered by welmessor on 2013-08-01

The time needed from triggering snapshotting to the snapshot image available is highly depending on the size of the image generated by snapshotting. The current snapshot to clone an instance is taking too much time especially when the image size is huge (base + instance disk). To clone an instance faster, we can copy qcow2 image (instance disk) and upload it into glance as a fast-snapshot image. Each time the user launch new instances from fast-snapshot image, first check if it exists in _base folder, if not get it from glance, second check its backing file image exists in _base folder, if not get it from glance and last directly copy the fast-snapshot image to the instance folder as “disk” file. This feature can be combined with live-snapshot feature (https://blueprints.launchpad.net/nova/+spec/live-snapshot-vms)to provide fast VM clone and restoring/rollback.

Blueprint information

Status:
Not started
Approver:
Vish
Priority:
Undefined
Drafter:
welmessor
Direction:
Needs approval
Assignee:
welmessor
Definition:
Drafting
Series goal:
None
Implementation:
Unknown
Milestone target:
None

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Whiteboard

Outcomes(not limited to below):
Reduce network load and storage pressure of glance since fast-snapshot images usually much smaller than a full image.
Reduce the time needed from triggering snapshotting to the snapshot image available
Provide ability for VM restoring/rollback in a shorter time
Etc.Outcomes(not limited to below):
Reduce network load and storage pressure of glance since fast-snapshot images usually much smaller than a full image.
Reduce the time needed from triggering snapshotting to the snapshot image available
Provide ability for VM restoring/rollback in a shorter time
Etc.

If you are still working on this, please re-submit via nova-specs. If not, please mark as obsolete, and add a quick comment to describe why. --johnthetubaguy (20th April 2014)

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Work Items

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