Automated snapshots with Btrfs

Sun, Oct 1, 2023 02:00 CEST

Tags: Arch Linux, Btrfs, Backup, Snapshots, snapper, snap-pac, pacman

Install snapper

pacman -S snapper

Make sure to have followed snapper’s recommendations regarding Btrfs subvolumes layout. Note that snapper creates a subvolume for snapshots at /.snapshots but with an unnecessary parent dependency on @.

To allow snapper to go through the configuration step, make sure you have unmounted any subvolume (or other) mounted at /.snaphosts and deleted any corresponding directory.

umount /.snapshots
rm -r /.snapshots

Create configuration for the root subvolume

snapper -c root create-config /

Then delete the subvolume automatically created by snapper

btrfs subvolume delete /.snapshots

And replace it with an independent @snapshots subvolume (if you had already created it, mkdir /.snapshots && mount -a should suffice).

Existing configurations can be listed with

snapper list-configs

You can edit configurations under /etc/snapper/configs/.

To enable automatic timeline snapshots simply install cronie and enable the corresponding systemd system service:

pacman -S cronie
systemctl enable --now cronie

To enable automatic pacman transactions snapshots, install snap-pac:

pacman -S snap-pac

You can configure snap-pac at /etc/snap-pac.ini.

To enable automatic snapshots on boot, enable snapper-boot.timer:

systemctl enable --now snapper-boot.timer

Existing snapshots can be listed with

snapper list