[arch-general] BTRFS, Rollback, Grub2

[C Anthony Risinger]

On Mon, Aug 20, 2012 at 7:53 AM, 1126
<mailinglists at elfsechsundzwanzig.de> wrote:
> Hello List!
>
> I can't seem to get rollback-support from mkinitcpio-btrfs to work
> properly. I've installed ArchLinux more or less like it is shown in the
> wiki-article btrfs-on-root:
> https://wiki.archlinux.org/index.php/Installing_on_Btrfs_root
>
> I changed it some, because I wanted to install ArchLinux on an
> encrypted btrfs-root.
>
> But my root-partition contains a __snapshot folder and an __active
> subvolume, but no subvolumes for __home and __usr and such, because I
> want to be able to make complete snapshots of my system.
>
> But when I want to create a snapshot, it asks me where I want to do it,
> but I can't give __snapshot as target-folder, because it don't exists in
> my system... ;)
>
> So: how should my btrfs-root be mounted in order to be able to make full
> use of the rollback-feature provided by mkinitcpio-btrfs?
>
> Thanks in advance for your help,

yeah ... someone or something completely botched that page, to where
it neither reflect the original design goals nor improves upon them.
far too much noise and pointlessness (like outbound links to FHS ...
who the @#$% cares?!)

in short, you need something like this in fstab or equiv:

/dev/disk/by-label/btrfs-root  /var/lib/btrfs-root  btrfs
defaults,noatime,subvolid=0  0  0

... you need to mount `subvolid=0` or `subvolid=5` (same thing)
somewhere, and make snapshots from there.  subvolid 5 (for which 0 is
an alias) is hard-coded to the top-level root.

maybe try this:

https://wiki.archlinux.org/index.php?title=Installing_on_Btrfs_root&oldid=185175

-- 

C Anthony