grub-install fails on software RAID

[andrew bezella]

On Tue, 2013-10-29 at 13:10 +0100, Olav Brinkmann wrote:
[...] 
> Everything seems OK so far, but during the installation run the default GRUB_PC/10-setup script fails at
> 
> root at thehost:~# $ROOTCMD grub-install --no-floppy "(md0)"
> /usr/sbin/grub-probe: Fehler: no such disk.
> Auto-detection of a filesystem of /dev/md0 failed.
> Try with --recheck.
> If the problem persists please report this together with the output of "/usr/sbin/grub-probe --device-map="/boot/grub/device.map" --target=fs -v /boot/grub" to <bug-grub at gnu.org>

hello -

i encountered a similar problem in ubuntu lucid and precise, where
attempts to install grub-pc onto a raid1 fail.  iirc i also hit it
during a recent debian upgrade, so i no longer think it's
ubuntu-specific (in the bug report below i make that claim).  it was a
different error message, but then again it's been awhile since my failed
attempts.  ymmv. 

the bug i commented on in hopes that it would be addressed: 
https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/462171
was closed w/the note "You need to install grub to the underlying
physical disks ( /dev/sda, /dev/sdb, etc ), not the raid array."  i've
edited the GRUB_PC/10-setup script to do that.  i've seen some comments
about superblock versions, etc. but i'm using the old .90 superblock on
the mirror underneath the rootfs w/o success.

however, (at the time) i also couldn't find anything explaining why this
had changed or grub2 docs detailing the issues.  so if anyone finds some
good related documentation (or counter-examples), please share!

thanks...

andy

-- 
andrew bezella <abezella at archive.org>
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