Re: grub2 & mdraid

[Oleg]

On Mon, Feb 10, 2014 at 12:50:25PM +0400, Andrey Borzenkov wrote:
> >
> >      grub --modules="part_msdos raid mdraid1x" --root-directory=/mnt 
> > /dev/sdb
> >      grub --modules="part_msdos raid mdraid1x" --root-directory=/mnt 
> > /dev/sdc
> >
> 
> Upstream does not have this command, you need to ask your
> distribution. Also in general grub2 is intelligent enough to figure

  Sorry, this is a typo - must be grub-install instead of grub.

> out what modules it needs; you need to have very good reasons and
> understanding of grub internals to manually specify them.
> 
> Try using
> 
> grub-install --boot-directory=/mnt/boot /dev/sdb
> grub-install --boot-directory=/mnt/boot /dev/sdc

This commands complains:

touch: cannot touch '/boot/grub/grub2-installed': Read-only file system
Installation finished. No error reported.

But now the system is booting ok. I test:

grub-install --root-directory=/mnt /dev/sdb

and the system boot again.

Ugh... Now i can't understand anything. Early i tried various versions of grub2
and various command options and now i confuse myself.

What is the difference between --boot-directory and --root-directory in my case?