Bug#491977: grub-probe fails with "Cannot find a GRUB drive for /dev/dm-N."

[Felix Zielcke]

Am Dienstag, den 29.07.2008, 08:39 +0200 schrieb martin f krafft:
> also sprach Robert Millan <rmh at aybabtu.com> [2008.07.29.0014 +0200]:
> > > debby:~# dmraid -r
> [...]
> > I don't know enough about mdadm to determine whose fault is it.
> > But it seems this is really a corner case problem, and only
> > happens in a very specific situation.  Therefore I'm lowering
> > severity.
> > 
> > I'm CCing the mdadm maintainers;  maybe they know how could
> > update-grub reliably obtain the physical device names in your
> > setup, or how to fix mdadm so that it outputs physical devices in
> > a way that makes update-grub happy.
> 
> mdadm has nothing to do with dmraid. md != dm.

Before Robert wrote the Mail I talked with him a bit about this.
I have myself a dmraid with a Nvidia nForce Motherboard Chip.
I never used mdadm to get my RAID0 working, I always used dmraid which
does this for me, without any interaction from me.

Am Montag, den 28.07.2008, 22:36 +0200 schrieb Moritz Naumann:
> debby:~# mdadm -D /dev/md0
..
>     Number   Major   Minor   RaidDevice State
> >        0     254        5        0      active sync   /dev/dm-5
> > 
> >        1     254        2        -      spare   /dev/dm-2
> > debby:~# 

But he used mdadm to get his Raid working, what you shouldn't do.
We have now the problem that GRUB sees it as a normal Linux software raid but then fails to install to it.
As Robert already said, we need the reail sdN or hdN devices but not the dm-N ones.
There are hopefully not many people who use the normal linux software raid to get there fake hardwarwe raid
controllers to work.