openSUSE uses btrfs's copy-on-write behavior to allow rollbacks. Any time you use the package management system to change system state on a machine using btrfs

openSUSE uses btrfs's copy-on-write behavior to allow rollbacks. Any time you use the package management system to change system state on a machine using btrfs the package manager actually snapshots the filesystem before (and I believe after) the install or remove. Due to COW this effectively only wastes the space for new versions of old files and snapshots can be cleared at will. It's a little weird to get used to, but it's actually a far more powerful "Oh Shit" button than package level rollback - a bad post-install script in a package that trashes /usr can usually be recovered easily if you read the docs and still have snapper (or can get a copy of it). Unfortunately RDBMSes don't usually play nice with copy on write filesystems, so it's much harder to do rollback there.