Is there a way to take a 'snapshot' of sorts and have my backup server mirror my live server, as a sort of testing environment? I know I've seen a lot of answers saying to use rsync. I'm not sure if that would work with what I have in mind.
My live server is currently on Ubuntu 10.04 and my backup server is currently on Ubuntu 12.04. I've also made changes in the partitioning that I wish to eventually move over to the live server once the backup server seems fine, but I want to revert to the old live server should anything go wrong.