openstack team mailing list archive

[Caitlin Bestler <Caitlin.Bestler@xxxxxxxxxxx>]

Lorin Hochstein asked:

> Are snapshots only supported on qemu/kvm, or do they work with other hypervisors as well? (Does Xen support qcow2 images?)

> Does OpenStack do anything with snapshots other than using them to generate new images? I was a little confused by the existence of the "Snapshots" pane in Diablo Horizon.
>  I originally thought snapshotting was just a qemu/kvm implementation detail about how nova created a new image from a running instance, so I didn't understand why there
> was a "Snapshots" pane in addition to an "Images" pane.

Snapshotting is a capability offered by may volume services, including all of the vendors at the Volume storage panel at the conference
(Netapp, Nexenta, Solidfire).

So the ability to create a snapshot, rollback to a snapshot and to create a new snapshot that references a snapshot as its base are strong
candidates for abilities to design for volume drivers. Any device that did not support this capability would simply state so. Snapshotting would
then have to be implemented with generic logic rather than vendor specific logic. Generally the vendor specific logic will be able to perform
the operation more efficiently than generic logic, otherwise the vendor would not have developed it.