Re: [libvirt] [PATCH] qemu: snapshot: Keep non-persistent changes alive in snapshot

On Fri, Oct 27, 2017 at 18:47:51 +0530, Madhu Pavan wrote: > On 10/27/2017 02:51 PM, Jiri Denemark wrote: >> I think this is actually a bit more complicated. When reverting to a >> snapshot, when reverting a snapshot we should revert both active and >> inactive configuration for backward compatibility and also because it >> makes sense. Imagine you made a snapshot of a running domain, played >> with the domain configuration and then reverted the state of the domain >> to the snapshot. Once you shutdown the domain and start it again you'd >> get a completely different machine. Of course, you actually may want >> such behavior. Thus we can't really guess whether a user wants to revert >> both active and inactive configuration or just one of them. The user >> should be able to tell us what to do (and we should revert both configs >> if no preference is given). >> >> However, for this to be really useful we need to store both active and >> inactive configurations when creating a snapshot of a running domain. > With the current behavior that I see from snapshot-list, I understood we > categorize the snapshots > as "Active (running, paused)" or "config(shutoff)" depending if the > snapshot was taken on an > active or inactive domain. With my use case what I observed was that the > revert of active > snapshot actually overwriting inactive domain configuration. I thought > only the "config" snapshot > alone can overwrite the inactive domain configuration. Hence this patch. > Are you suggesting we > should have both active and inactive domain configurations to be saved > for an active guest and > restore (both by default) OR (provide options to select)? Yes, exactly.