Dedoimedo published a tutorial about creating BTRFS snapshots

BTRFS, pronounced Butter FS, is a relatively new filesystem for Linux, based on Sun's ZFS, the one company behind most great UNIX-like inventions in the past 25 years, until devoured by Oracle. Never mind that. BTRFS is still considered unstable and thus not suitable for production environments. However, the filesystem comes with many useful features and capabilities that are worth exploring. One such is the ability to create snapshots of your system.

Let me elaborate. Snapshots are time-dependent system states. In a way, if you copy a file and create a backup, you essentially create a snapshot, relevant to the moment of copying. This can be done anywhere, anytime. But this is not a filesystem feature. Think of a filesystem that actually can managed multiple replicas of your files, within its own structure, and allow you to use them as you please. Sounds neat, let us explore.

  How to create and use BTRFS snapshots - Tutorial