Definitely a terrible idea to attempt but you're not wrong in wanting something like this. You have to be 100% sure that the backup has the exact same state as the original 100% of the time with no microsecond where it might be different.

All filesystem writes should be done against a network drive or distributed store. You should also be 100% sure that the backup doesn't kick in prematurely and that it is impossible for 2 of them to be running at the same time.

At Mutiny we allow a node to run on multiple devices and it's decent enough for us to resolve when problems occur but in a routing node context, any bug that causes revoked funds will be close to impossible to get back.