If your snapshots are taking up too much space you can follow this procedure:
- Delete all snapshots.
- Enable BTRFS quotas.
- Reboot.
- Perform a BTRFS scrub.
- Perform a BTRFS balance.
- Reboot
- Configure your snapshot retention policy.
- Take a new system snapshot.
Caveats:
Enabling BTRFS quotas can cause issues on some systems. This is rare, but this feature is disabled by default for this reason. Enabling BTRFS quotas will allow far more accurate tracking of free space on BTRFS partitions.
Deleting all snapshots is not a good idea if you are currently encountering any serious bugs on your system. If your system is operating properly, then deleting all snapshots should not be particularly risky. Just be sure to take a new snapshot before performing any changes to your system such as installing new programs or performing a system update.