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# Timeshift

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- Btrfs
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Timeshift is a tool originally created by Tony George, that is now part of the Xapp project.

Timeshift helps create incremental snapshots of the file system at regular intervals, which can then be restored at a later date to undo all changes to the system.

It supports rsync snapshots for all filesystems, and uses the built-in snapshot features for Btrfs drives configured to use the `@` and `@home` subvolume layout for root and home directories respectively.

## Installation

Install the timeshift package and enable/start your chosen cron scheduler (see cron#Configuration). This will ensure that snapshots scheduled within the Timeshift application run as intended.

Note The timeshift package currently takes a hard dependency on cronie as the cron scheduler.

Alternatively, timeshift-systemd-timerAUR can be installed instead of using a cron scheduler.

## Configuration

Timeshift can be fully configured using the `timeshift-gtk` graphical user interface, but if running graphical applications is not an option, its configuration file can be edited directly. Copy the template file `/etc/timeshift/default.json` to `/etc/timeshift/timeshift.json` and edit settings you want to change.

Note

- If you want to enable btrfs mode, make sure that your subvolume layout is compatible. See #Configuring btrfs snapshots.
- The exclusion patterns are applied from top to bottom, with the first match overriding subsequent ones.
- The exclude option is not supported in Btrfs mode. See #Excluding directories from Btrfs snapshots.

Here is an example of a rsync-based configuration with three weekly snapshots and rules to exclude the `/var/cache`, `/var/tmp` and `/home/archie` directories, while including the `/home/archie/.config` directory and its content into the snapshots:

    /etc/timeshift/timeshift.json

    {
        "backup_device_uuid" : "root-partition UUID",
        "do_first_run" : "false",
        "btrfs_mode" : "false",
        "include_btrfs_home_for_backup" : "false",
        "include_btrfs_home_for_restore" : "false",
        "schedule_weekly" : "true",
        "count_weekly" : "3",
        "date_format" : "%Y-%m-%d %H:%M:%S",
        "exclude" : [
            "/var/cache/**",
            "/var/tmp/**",
            "+ /home/archie/.config/***",
            "/home/archie/**"
        ],
        "exclude-apps" : []
    }

## Usage

Snapshots can be managed through the `timeshift-gtk` graphical user interface, as well as the `timeshift` command-line user interface tool.

Tip Use the `--scripted` key when using `timeshift` in scripts.

Listing snapshots:

    # timeshift --list

Creating a snapshot:

    # timeshift --create --comments "comment"

Restoring a snapshot:

    # timeshift --restore --snapshot "snapshot"

Deleting a snapshot:

    # timeshift --delete --snapshot "snapshot"

## Configuring btrfs snapshots

Timeshift requires a flat Btrfs layout with subvolumes for `/` and optionally `/home` being named as `/@` and `/@home`.

### Making a supported Btrfs layout during installation

The instruction below assumes that you are following the installation guide.

Right after the Btrfs filesystem is created and mounted to `/mnt`, create subvolumes named `/mnt/@` and `/mnt/@home`. Unmount `/mnt` and mount the subvolumes using the `subvol` parameter:

    # mount -o subvol=@ /dev/root_partition /mnt
    # mount --mkdir -o subvol=@home /dev/root_partition /mnt/home

Proceed with the installation as normal.

Warning Make sure to remove the `subvolid` mount parameter for `/` and `/home` from the Fstab file if it was generated using genfstab, or you will be unable to boot after restoring from a snapshot.

### Converting an installed system to the compatible Btrfs layout

The following instructions assume that the system is installed in the top-level (ID=5) subvolume, you may need to adapt these depending on your configuration.

Start by creating a snapshot of your root named `/@` and mount it to `/mnt`:

    # btrfs subvolume snapshot / /@
    # mount -o subvol=@ /dev/root-partition /mnt

Create the `/@home` subvolume, move the user data into it and mount it at `/mnt/home`:

    # mv /mnt/home/* /@home
    # mount -o subvol=@home /mnt/home

Mount your EFI system partition to `/mnt/esp` if you have one. Chroot into `/mnt`, reinstall and reconfigure the boot loader. For an amd64 EFI system with GRUB, just running:

    # grub-install --target=x86_64-efi --efi-directory=esp --bootloader-id=GRUB
    # grub-mkconfig -o /boot/grub/grub.cfg

would be enough, however if you use any other bootloader that has no automatic configuration, you need to manually add `rootflags=subvol=@` to the kernel options (see Kernel parameters#Boot loader configuration).

Edit the fstab file so that the entry for `/` contains `subvol=@` mount option, and add an entry for `/home` with `subvol=@home` mount option. Example of how it may look like:

    ...
    UUID=d8efe946-8d28-40d6-943a-70af51a8d2cd  /       btrfs   defaults,subvol=@      0    0
    UUID=d8efe946-8d28-40d6-943a-70af51a8d2cd  /home   btrfs   defaults,subvol=@home  0    0
    ...

Exit the chroot, reboot and confirm with the `mount` command that everything is done correctly. Mount the toplevel using `mount -o subvolid=5 /dev/root-partition /mnt` and cleanup the old root.

### Excluding directories from Btrfs snapshots

Btrfs mode does not support the exclusion of individual files and directories from snapshots. However, it is possible to work around this to some extent by creating additional subvolumes at the top-level and mounting them in place of directories, which will effectively exclude them.

Here is an example of how to exclude the `/var/log` directory, to prevent the system logs from rolling back and make it easy to inspect them after a system breakage:

Start by mounting the top-level and create the subvolume inside of it:

    # mount -o subvolid=5 /dev/root-partition /mnt
    # btrfs subvolume create /mnt/@var_log

Add a new entry for it to fstab:

    UUID=root-partition-UUID  /var/log   btrfs   defaults,subvol=@var_log  0    0

### GRUB entries for btrfs snapshots

To add snapshots to the GRUB menu each time GRUB configuration is generated, install the grub-btrfs package. It comes with the `grub-btrfsd.service`, which can be enabled to automatically update the GRUB configuration whenever a new snapshot is created.

Note `grub-btrfsd` requires the inotify-tools package to function

To make grub-btrfsd work with Timeshift, edit the service by running:

    # systemctl edit --full grub-btrfsd

and change the line:

    ExecStart=/usr/bin/grub-btrfsd /.snapshots --syslog

to:

    ExecStart=/usr/bin/grub-btrfsd --syslog --timeshift-auto

After saving the changes, restart the service.

## Troubleshooting

### Timeshift GUI not launching on Wayland

Xwayland will only allow the user who started the X server to connect clients to it (see Privilege elevation for graphical applications#XWayland).

Due to Timeshift requiring root permissions, attempting to launch the Timeshift GUI via an application launcher or a terminal with the command `timeshift-launcher` will result in an error containing `xhost: command not found`.

Users encountering this error may also be presented with their authentication agent prompting for a password, only to find that the Timeshift GUI does not launch after entering the password. [1][dead link 2025-03-15—HTTP 404] This is because the command `timeshift-launcher` requires the xorg-xhost package: install it.

If GTK cannot open your display and you get a warning message in the terminal, it means that the root user need the access to the graphical X server (Display :0, :1, etc.)

Normally only the user who started the graphical session can open new windows in your compositor and since your need to execute timeshift with the root user, you are not able to open the GUI

    $ xhost +SI:localuser:root

Warning This command can grant any local user access to your X screen. It is advised against running `xhost` on multi-user systems. See xhost and Privilege elevation for graphical applications for more details.

### Delete button does nothing/"Directory not empty" error

If the delete button silently fails in GUI and `timeshift --delete --snapshot snapshot` results in

    E: ERROR: Could not destroy subvolume/snapshot: Directory not empty

this means the snapshot contains one or more nested subvolumes and those need to be removed manually. In order to do so, you need to mount the toplevel subvolume and see the subvolume list:

    # mount -o subvolid=5 /dev/root_partition /mnt
    # btrfs subvolume list /mnt

If you see any subvolumes located inside the snapshot, make sure they do not contain anything you would like to copy first and remove them by running:

    # btrfs subvolume remove /mnt/timeshift-btrfs/snapshots/snapshot/@/path/to/subvolume

And remove the snapshot using timeshift as normal. Alternatively, you can remove the whole snapshot and all the nested subvolumes by running `rm -rf /mnt/timeshift-btrfs/snapshots/snapshot`.

Typically, this issue occurs because systemd-nspawn creates `/var/lib/machines` and `/var/lib/portables` subvolumes automatically. You can avoid this by creating them as directories in advance [2]

    # mkdir -p /var/lib/machines /var/lib/portables

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