Rollback To A Working State With btrfs + apt-btrfs-snapshot On Ubuntu 12.10
This tutorial explains how you can revert failed apt operations (like apt-get upgrade)
and roll back to the previous system state with apt-btrfs-snapshot on
an Ubuntu 12.10 system that uses the btrfs file system.
apt-btrfs-snapshot creates a snapshot of the system before the apt
operation. Being able to easily restore the previous system state after a
failed apt operation takes away much of the pain system administrators
have to deal with normally and is one of the greatest features of the
btrfs file system.