Automatic System Snapshots

Automatic system snapshots are configured independently of the chosen file system when the corresponding setting is enabled (see “Expert Settings” ⇒ “System Maintenance Tools” ⇒ “Configure Automatic System Snapshots”). These snapshots are created each time a complete system upgrade is performed. On ZFS and BTRFS filesystems, these snapshots are atomic, meaning they occur almost instantaneously and ensure a consistent state by capturing all files at the exact same point in time.

The initial snapshot is taken at the end of the installation process. Additionally, for XFS and EXT4 filesystems, this strategy offers the advantage that the first snapshot in a running system requires significantly less time (typically under 5 seconds), similar to subsequent snapshots.

Recovery Procedure

If your system fails to boot, you can recover by booting from the ISO, which provides access to a rescue system. Within this environment, you can use the commands below to restore a snapshot.

Note: As these are “system snapshots,” your home directory and other volumes remain unchanged. This allows you to restore a system snapshot without affecting your personal files.

Filesystem-Specific Instructions

ZFS

1. List Available Snapshots:

   zfs list -t snapshot
   

   Example output:

   ❯ zfs list -t snapshot 
   NAME                                                    USED  AVAIL  REFER  MOUNTPOINT
   ditana-root/ROOT/default@autosnap_2024-11-21_23-14-41   453K      -  3.96G  -
   ditana-root/ROOT/default@autosnap_2024-11-21_23-25-28   394K      -  3.96G  -
   ditana-root/ROOT/default@autosnap_2024-11-21_23-26-06  1.05M      -  3.96G  -
   

2. Restore a Snapshot:

   sudo zfs rollback <SNAPSHOT_NAME>
   

   Example:

   sudo zfs rollback ditana-root/ROOT/default@autosnap_2024-11-21_23-27-12
   

BTRFS, XFS, EXT4

Automatic snapshots are managed by the timeshift-autosnap package and do not require additional configuration via Timeshift. This package ensures that system snapshots are created automatically during each Arch Linux system upgrade.

1. List Available Snapshots:

   sudo timeshift --list
   

   Example output:

   > sudo timeshift --list
   Mounted '/dev/dm-0 (sda4)' at '/run/timeshift/195216/backup'
   Device : /dev/dm-0 (sda4)
   UUID : cca08543-da4e-44a0-839b-d20e6f258c9a
   Path : /run/timeshift/195216/backup
   Mode : RSYNC
   Status : OK
   1 snapshots, 14.2 GB free
   
   Num Name Tags Description
   --------------------------------------------------
   0 > 2024-12-21_18-04-37 0 after installation of Ditana GNU/Linux
   

2. Restore a Snapshot:

   sudo timeshift --restore --snapshot <SNAPSHOT_ID>
   

   Example:

   > sudo timeshift --restore --snapshot 2024-12-21_18-04-37
   Mounted '/dev/dm-0 (sda4)' at '/run/timeshift/208067/backup'
   
   **************************************************************************
   * To restore with default options, press the ENTER key for all prompts! *
   **************************************************************************
   
   Press ENTER to continue...
   
   Re-install GRUB2 bootloader? (recommended) (y/n): n
   

   Important Note 1

   Do not follow Timeshift’s recommendation to reinstall GRUB2, as Timeshift assumes an update-grub tool is available. If you need to update GRUB after restoration, execute:

   grub-mkconfig -o /boot/grub/grub.cfg
   

   Important Note 2

   Unlike ZFS snapshots, after restoring with Timeshift, you must run:

   sudo rm /var/lib/pacman/db.lck
   

   This ensures a consistent state. The necessity arises not from Timeshift itself, but from the sophisticated strategy employed by zfs-autosnap.