From Mageia wiki
Contents
Summary
Add support to boot from Btrfs subvolumes/snapshots. This allows to make a snapshot of the system and then rollback to it.
Owner
- Name: Nikita Krupenko
- Email: krnekit@gmail.com
Resources
List here people who will be implied in this feature (packagers, QA, doc, ...)
Current status
- Targeted release: Mageia 6
- Last updated: 2025/05/09
- Percentage of completion: 0%
Detailed Description
The feature can be implemented in a two ways:
- Use special name for subvolume used for boot, for example '@' (this is how it's done in Ubuntu). In this way, if one want to boot from different subvolume, it can be done by renaming @ to something else and new root subvolume to @.
- Set default subvolume on partition. This does not work with default GRUB2, as support for using default subvolume removed from it and requires special patches for GRUB2 (this is how it's done in SUSE).
The simplest solution is first one, as it requires at least installer to be able to create subvolume and install into it, instead of just using root directory of partition (i.e. /@/ instead of /) and add mount option to use this subvolume (i.e. subvol=@).
In fact, Mageia 5 can be installed on a subvolume, with some tricks and it works, even on partition placed into encrypted LVM.
Why it would be good for Mageia to include it
Because people can make a snapshot of working system and then rollback to it if something would broke.
Test case
- Install the system on a Btrfs subvolume.
- Create a snapshot of the current subvolume, used for foot filesystem.
- Check, if changing current subvolume for root fs is working and system can boot.
