timepatrol

BTRFS snapshots manager and rollback tool

Timepatrol is a BTRFS snapshot manager and a rollback tool in a single script. There are great tools out there which do the same, like Timeshift and Snapper, for example, but I still prefer Timepatrol because:

• Easy to rollback to any snapshot.
• Minimal dependency: ruby.
• Outputs fit in half screen. Perfect for window manager users.
• It has colors! Although it can be disabled.

In fact, it was written based on my personal needs but it may be of interest of a few people also.

In principle it can be used in any Linux distribution. Arch users will benefit from the pacman pre and post hooks which I found to be very handy in the day-to-day use.

Disclaimer

This is an early, experimental project. Use at your own discretion.

Dependency

• ruby

Installation

Arch

From AUR, which I maintain myself.

Other Linux

1. git clone https://github.com/abdeoliveira/timepatrol
2. cd timepatrol
3. sudo ./install.sh

Uninstall

Arch

sudo pacman -Rs timepatrol-git

Other Linux

• Run: sudo rm -r /usr/bin/timepatrol /etc/timepatrol

Configuration

Copy the example configuration file as

cp /etc/timepatrol/config-example /etc/timepatrol/config

Then, check the comments in config file for directions and adjust it as per your system.

A note regarding /etc/fstab: The default installation in some distributions (Arch for instance) include the subvolid information in fstab for mounting points. Since rollbacks change such a number I recommend you omit the subvolid in the / entry. Mine reads as follows:

# Static information about the filesystems.
# See fstab(5) for details.

# <file system> <dir> <type> <options> <dump> <pass>
# /dev/mapper/ainstnvme0n1p2
UUID=054b4420-a2e0-41b1-8d66-8cc7198d8b55	/         	btrfs     	rw,relatime,ssd,space_cache=v2,subvol=/@	0 0

# /dev/mapper/ainstnvme0n1p2
UUID=054b4420-a2e0-41b1-8d66-8cc7198d8b55	/home     	btrfs     	rw,relatime,ssd,space_cache=v2,subvolid=257,subvol=/@home	0 0

# /dev/mapper/ainstnvme0n1p2
UUID=054b4420-a2e0-41b1-8d66-8cc7198d8b55	/var/log  	btrfs     	rw,relatime,ssd,space_cache=v2,subvolid=258,subvol=/@log	0 0

...

Usage

Type sudo timepatrol help for a basic list of commands. They are

• list: lists snapshots limiting shown comments 110 characters.

• list-verbose: lists snapshots without limit to comment characters.

• list-grep 'STRING': lists snapshots containning STRING in comments.

• snapshot 'OPTIONAL COMMENT': takes a snapshot of / with (optional) given comment.

• snapshot-keep 'OPTIONAL COMMENT': same as above plus it adds a protection against automatic deletion. Automatic deletion is set via the MAXIMUM_SNAPSHOTS variable in the /etc/timepatrol/config file. Protected snapshots have a * mark next to their IDs, and they do not count against the MAXIMUM_SNAPSHOTS variable. For example, if 2 snapshots are protected and MAXIMUM_SNAPSHOTS = 20, then the maximum number of snapshots will be 22.

• change-comment ID 'NEW COMMENT': replaces current COMMENT of snapshot ID by 'NEW COMMENT'.

• delete: deletes a snapshot. It accepts individual ID numbers and ranges. For example: sudo timepatrol delete 1,10,20-23 will delete snapshots whose IDs are 1, 10, 20, 21, 22, and 23. The delete command also accepts the following substring selectors: date=, time=, kernel=, and comment=. See the example of usage below:

oliveira@arch:~$ sudo timepatrol delete time=16:
*[208]  2024.08.12  16:30:05  6.10.4-arch2-1  Niri OK 
 [258]  2024.08.20  16:07:01  6.10.5-arch1-1  PRE: install libxp (1.0.4-3) 
 [259]  2024.08.20  16:07:56  6.10.5-arch1-1  PRE: remove libxp (1.0.4-3) 
 [260]  2024.08.20  16:26:31  6.10.5-arch1-1  PRE: install libxp (1.0.4-3), install 
                                              openmotif (2.3.8-3), install t1lib 
                                              (5.1.2-8) 
 [264]  2024.08.21  10:16:52  6.10.6-arch1-1  PRE: upgrade timepatrol-git 
                                              (r149.7e4bff6-1 -> r151.3f4f304-1) 
:: Confirm deletion of the selected snapshot(s) above? [y/N]

Note that all snapshots containing the user-given substring 16: in the time field were selected for deletion. I recommend you play with the other selectors. In any case, the user will always be prompted to confirm the deletion with the No answer being the defaut.

• toggle-keep: Toggles between protect and unprotect snapshots. It accepts an individul ID, list of IDs, ranges and selectors similar to the delete command above.

• rollback: rolls back the installation to a previous, selected snapshot state. Some notes:

(i) rolling back to a snapshot whose kernel is different from the running kernel is not allowed (the script will ABORT). You must adjust the current kernel (downgrade/upgrade), then reboot (so it is loaded), then try to rollback.

(ii) Plese read the recommendation regarding the /etc/fstab file before rollback.

(iii) Reboot immediately after kernel upgrade. To be on the safe side, reboot immediately after any system upgrade. See the Troubleshooting section also.

Bash completion

Arch

Install bash-completion.

Other Linux

Install bash-completion and then copy and paste the contents of completions/timepatrol to your ~/.bashrc:

cat completions/timepatrol >> ~/.bashrc

Periodic, automatic snapshots

For a 24/7 running machine, probably the simplest way is setting a cronjob as root.

For notebooks, I recommend simplecron, which I mantain myself.

Troubleshooting

Unbootable system after rollback

Many factors can lead to an unbootable system after rollback. For example, you may have upgraded the kernel, didn't reboot and rollback.

I have no sufficient knowledge to cover all system-rescue situations, but I would say that the following steps would fit in most cases:

1. Boot using a live media
2. Chroot into your (broken) system
3. Mount all partitions (eg. mount -a)
4. Reinstall your boot loader. Alterativelly, you can try to downgrade the kernel. If you are on Arch, try this second route since pacman is very good on setting things up.
5. Exit chroot. Reboot.

TODO

• timepatrol check in order to check the integrity of the configuration file.