Snapshot 'c1-20201218-03' cannot be restored due to subsequent snapshot(s). Set zfs.remove_snapshots to override

Jimbo · December 18, 2020, 11:07am

I am using LXD 4.0.4 , when trying to restore a snapshot I get the following error message

Snapshot 'c1-20201218-03' cannot be restored due to subsequent snapshot(s). Set zfs.remove_snapshots to override

So I ran

$ lxc storage set default volume.zfs.remove_snapshots=true

Now I get a different error message

More recent snapshots must be deleted: [c1-20201218-04]

Am I misunderstanding something here, I thought by setting that setting it will delete subsequent snapshots.

tomp · December 18, 2020, 11:14am

This looks like a bug to me, there appears to be a missing return nil at the end of this block:

github.com

lxc/lxd/blob/stable-4.0/lxd/storage/backend_lxd.go#L2057-L2084


		snapErr, ok := err.(drivers.ErrDeleteSnapshots)
		if ok {
			// We need to delete some snapshots and try again.
			snaps, err := inst.Snapshots()
			if err != nil {
				return err
			}
			// Go through all the snapshots.
			for _, snap := range snaps {
				_, snapName, _ := shared.InstanceGetParentAndSnapshotName(src.Name())
				if !shared.StringInSlice(snapName, snapErr.Snapshots) {
					continue
				}
				// Delete if listed.
				err := b.DeleteInstanceSnapshot(snap, op)
				if err != nil {
					return err
				}

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If you try and restore again it should work as it appears it will have removed the problem snapshots already.

Jimbo · December 18, 2020, 11:18am

Nope. No snapshots are deleted.

tomp · December 18, 2020, 12:20pm

You’re right, have reproduced issue and this PR fixes it:

tomp · December 18, 2020, 1:30pm

This has now been merged.