[arch-general] BTRFS + Rollback + Subvolumes

[C Anthony Risinger]

On Wed, Jul 11, 2012 at 3:10 AM, 1126
<mailinglists at elfsechsundzwanzig.de> wrote:
>
> So I now have a subvolume __active which represents /, one for home, one for usr
> and one for var.

[...]

> Am I missing something or is just not possible to use different subvolumes (like
> __active, home, usr, var) and being able to rollback your system during boot? As
> far as I know btrfs-snapshots are not recursive. So wouldn't it be better
> (being-able-to-rollback-wise) to just have one subvolume so that you can really
> rollback everything in case something went wrong? Or is there a way to combine
> the benefits of having different subvolumes and still being able to rollback the
> system?

nah, you're not missing anything, and are absolutely correct.

i've no idea why the page now says what it does -- it appears to have
been completely ... ehm ... butchered since myself and Eigrad/Andrew
initially wrote it, oooh about 18 months ago:

https://wiki.archlinux.org/index.php?title=Installing_on_Btrfs_root&oldid=129890

... nor am i sure why so much red and yellow was strewn about;
everything is (was?) confirmed/factual.  sorry :-(

i would recommend dropping the subvols ASAP, and reviewing the
original wiki linked above.

alas, i've heard -- and "seemingly" confirmed -- inklings that GRUB2
now supports booting from a btrfs subvol -- the magic feature required
to perform kernel-level rollbacks! yay! as i have long since used
GRUB2 on all my machines and am somewhat familiar with scripting it, i
expect to make some extensive updates soon-ish-ly.

i'm not sure how relevant/beneficial this discussion can be for
everyone else here (though in general, the use-case itself is
certainly worthy of discussion) -- should you have pointed/specific
questions/problems feel free to ask in the AUR comments.

-- 

C Anthony