Booting from RAID (was: Re: booting btrfs)

[Andrey Borzenkov]

On Mon, Jan 13, 2014 at 9:53 AM, Chris Murphy <address@hidden> wrote:

> There are other problems with Fedora that prevent this from being usable now, 
> including grubby which can't update grub.cfg during kernel updates, when 
> /boot is on a Btrfs subvolume. So I have no present implementation, it's a 
> question how to boot from Btrfs raid1 in the future, and have as little 
> duplicative efforts as possible. Also, my argument is that if a GUI installer 
> permits the user to create bootable raid1, that it should also properly 
> configure all drives, and the static ESP grub.cfg, to make the system 
> bootable. Otherwise the user has to do this manually which requires esoteric 
> knowledge beyond most users. If the system really isn't bootable in the face 
> of a disk failure, then I think a GUI installer shouldn't even offer bootable 
> raid1 (Btrfs or otherwise) as an option.

openSUSE supports /boot on RAID1 and will simply run grub-install for
each device (it limits bootloader location to MBR in this case). This
can be optimized of course noticing that you need to create image just
once, but it works. Same can be used in case of btrfs.

I'd like to have some more generic case of having several boot block
locations independently on RAID (effectively grub-install /dev/sda
/dev/sda3 /dev/sdb ...); grub-install part looks more or less
straightforward, but modifying grub-setup part is more challenging.