Re: rollback to a snapshot

[Phillip Susi <phill@thesusis.net>]

Bernd Lentes <bernd.lentes@helmholtz-muenchen.de> writes:

> Could you propose a setup here which does not use top level subvolumes ?
> I found it very frustrating that everyone says "BTRFS is great, you can do snapshots and easily rollback".
> Because in reality rollback is not easy. How can i avoid to use top level subvolumes ?
> I have some Suse boxes which seem to have a correct default setup. But when i install e.g. an Ubuntu box
> i really don't know how to setup BTRFS manually.
> There was a great Wiki (https://archive.kernel.org/oldwiki/btrfs.wiki.kernel.org/index.php/Main_Page.html),
> but now it's outdated. Is there something new ?

The last time I installed Ubuntu on btrfs, the installer automatically
created a top level subvolume named @ and actually installed the system
in that subvolume, then configured grub to tell the kernel to mount the
root btrfs volume with the flag subvol="@" so that the system would boot
normally.  Then you just mount the real root of the filesystem somewhere
else and make a snapshot of the @ subvolume.  When you want to roll
back, you just rename @ to something else, and either rename or create a
new writable snapshot from your previous snapshot and name it @, then
reboot.