Bug#526615: fails to install to RAID across virtual (kvm/virtio) disks

[Felix Zielcke]

Am Sonntag, den 03.05.2009, 10:12 +0200 schrieb martin f krafft:
> 
> also sprach martin f krafft <madduck at debian.org> [2009.05.02.1107
> +0200]:
> > However, trying to install to a system with RAID1 across two virtual
> > disks, I run into two errors, depending on which approach I take:
> 
> Those two errors are separate issues, thus the clone. Let's pull
> them apart:
> 
> >   mdadm-test:/boot/grub# grub-install /dev/md0
> >   grub-setup: error: Unknown device number: 254, 0
> 
> This is the current bug #526615: grub tries to be smart and analyses
> /dev/md0 to find the component devices, but then does not know how
> to handle device major number 254 (kernel reserved for
> local/experimental), runs into the corner and puts on the stubborn
> face.
> 
> Instead, I think it would make sense if grub would simply treat the
> block device as a plain block device and resist trying to be smart
> about it.
> 
> For safety, maybe this could be done with a flag,
> --unknown-as-block, or more explicit e.g. grub-setup
> --block-devices=/dev/vda,/dev/vdb.
> 
> I think this would also address #525879.
> 
> 

We currently use in grub-setup ioctl (GET_ARRAY_INFO) and ioctl
(GET_DISK_INFO) and unfortunately they return the major and minor of the
device and not the name of the device file.
See util/raid.c for the grub2 code.
If you need to specify the devices of which md0 consists, then you could
just use grub-install /dev/sda etc.

-- 
Felix Zielcke