Re: Question about btrfs as root filesystem

Chris Murphy
Fri, 08 Nov 2013 17:44:55 -0000

On Nov 8, 2013, at 5:55 AM, Goffredo Baroncelli <kreijack@libero.it>
<kreijack@libero.it> wrote:
>
> Instead of using set-default, I am used to rename the subvolume.
> I.E. I assume that the root filesystem is a subvolume always called
> "__active".
> When I want to rollback, I rename "__active" in
"__broken" (or
> remove it), then I rename (or re-snapshot) "snapshot-yyyymmdd"
> in "__active".
>
>>> That way, we ensure the best compatibility and lowest maintenance,
>> as we don''t overwrite default init functions.
>>
>> I''m sympathetic to the alternative problem, which is that you
need to
>> alter grub.cfg to use the proper rootflags=subvol= to explicitly use
the
>> proper snapshot, and also it would mean altering the /etc/fstab within
>> that snapshot.
>
> With rename you can address both the issues

Now I don''t know what snapshot that is, since it''s just
renamed to some non-descriptive name like "root" which happens to, by
convention, always be the active root. This is the problem with using user
domain to store contextual metadata. We need another way to do this, rather than
inject these changes into filename/foldername which are primarily user domain.
And we need agreement on a right way to do this rather than distribution
convention.

We need some distribution collaboration in this area, or this is going to turn
into an end-user pain point, with multiboot users top on the list of the
injured.


Chris Murphy--