Re: [libvirt] [PATCHv2 19/20] snapshot: qemu: Add support for external snapshot deletion.

On 11/06/12 23:39, Eric Blake wrote: > On 11/01/2012 10:22 AM, Peter Krempa wrote: >> This patch adds limited support for deleting external snaphots. The > > s/snaphots/snapshots/ > >> machine must not be active and only whole subtrees of snapshots can be >> deleted as reparenting was not yet implemented for external snapshots. > > These are reasonable restrictions for the first implementation. We may > relax some of them later - for example, if qemu adds support for doing > blockcommit from the active layer, then that would let us do a live > deletion of an external snapshot. > >> ---

> > 6. I created an external checkpoint, did some experiments, and want to > remember those results; but I also want to go back to the checkpoint and > do some more experiments on a different branch. Solution: here, we need > the ability to create NEW qcow2 files that also wrap the common base > image. Since virDomainRevertToSnapshot doesn't have a way for us to > pass in the new file names we wish to use, this needs to go through > virDomainSnapshotCreateXML, which needs a new flag that says that we are > simultaneously reverting to the state of an existing snapshot and > creating a new snapshot from that point rather than at the current state > of execution. I saw your submission. But this will probably have to be a 2 step procedure: 1) create a snapshot at the original branch to have a point to return to 2) create the branch and revert to that point in time Otherwise it will be hard to return to that original branch. Basically we need some kind of "current" snapshot in each of the branches. Technically that should be easy for a management application, but it won't be that comfortable to do in virsh.