Hopefully, what you have seen so far in btrfs will be of interest, but, of course, there is always much more to see and learn. We will now look at snapshots. Btrfs snapshots can be used as read-only or read/write copies of your data. With btrfs as a Copy-on-Write-based filesystem, there is no need to copy large amounts of data across because we only need to copy the data when it changes. In the meantime, the original data is linked to the new location. In this way, a snapshot of a large filesystem can be taken instantly. Snapshots can be put to use in a couple of ways:
As part of a backup solution where you may be concerned with open files affecting the backup; the snapshot will be created as read-only. Subsequently, you will implement a backup of the snapshot. In this way, the backup will be of the host filesystem at the point in time that the snapshot was created.
Snapshots can be useful where you feel that rolling back to the original data may be useful, perhaps in...