Having some issues understanding how to revert snapshots on ubuntu 14.04 using KVM...
Until now i have been using internal snapshots, however due to space issues (space not being re-allocated after snapshots deleted) I want to move to external snapshots...
I understand (although haven't tried yet) that i can merge, pull things inbetween snapshots, however i can't seem to understand how to revert to a snapshot...
Example: base <-- snap1 <--- snap2 <--- snap3 (current)
How can I go back to snap2 if i want to discard snapshot3?
... And How can I start a new instance that is a "clone" of snap2 so that i can continue testing things on it and perhaps at a later point discard it and go back to snap3 ?
This was easily made with internal snapshots using snapshote-revert, however i can't seem to understand how it works with external snapshots... Some examples would be great. Thanks
virsh edit VMNAMEand point the disk at the location of snap2Don't forget to delete snap3
EDIT: branching out
In order to be able to switch back to a snapshot in a chain, without corrupting the entire chain after the current snap, you need to create a branch. Using your example, you stop the VM, take a new snap of snap2 (e.g. snap2branch1) and use it to play with snap2, without actually effecting snap2. If the changes are acceptable, you abandon snap3 (and the rest of the chain, after it), rename snap2branch1 to snap3, and keep working. If you prefer to dump the changes and return to snap3, you simply abandon the branch, and switch the VM to using snap3 again.