Fails to install grub when (partitioned?) md array is present

[Iain Lane]

Binary package hint: ubiquity

Hiya,

I'm trying to install Lucid A3 on my system, which has a (maybe) nonstandard partition layout.

  2x1T drives in a raid0 array, assembled in the live environment with mdadm --assemble --scan
  1x500G drive, split into NTFS, ext4 and swap partitions, like this:

  ubuntu@ubuntu:~/m$ blkid
  /dev/md0p1: UUID="a9c7370f-f9eb-4d31-bc7b-7fb3def0a4f8" TYPE="ext4"
  /dev/sdc1: UUID="4EF8EC4AF8EC323F" TYPE="ntfs"
  /dev/sdc2: UUID="c1d654eb-a3ba-42b7-a1b7-0a8a34b05863" TYPE="ext4"
  /dev/sdc5: UUID="7e0bab34-637c-42de-a1c9-165a348ae78d" TYPE="swap"

I installed as normal with Ubiquity, selecting /dev/md0p1 as / and /dev/sdc5 as swap. I did not format /dev/md0p1, as this contains my user data. The installer failed to install grub. I elected to continue without a boot loader and to try and fix this myself.

Installing grub2 in a chroot results in:

  root@ubuntu:/# dpkg-reconfigure grub-pc
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  Auto-detection of a filesystem module failed.
  Please specify the module with the option `--modules' explicitly.
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  Auto-detection of a filesystem module failed.
  Please specify the module with the option `--modules' explicitly.
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  Auto-detection of a filesystem module failed.
  Please specify the module with the option `--modules' explicitly.

Futher futile attempts resulted in various messages:

  root@ubuntu:/# grub-install --recheck /dev/md0 --modules="mdraid raid"
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  /usr/sbin/grub-setup: error: no mapping exists for `md0'.

  root@ubuntu:/# grub-install --recheck /dev/sdc --modules="mdraid raid"
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  /usr/sbin/grub-probe: error: no mapping exists for `md0'.
  You attempted a cross-disk install, but the filesystem containing /boot/grub does not support UUIDs.

I then attempted to fall back to grub, but switched to grub2 in order to obtain more logs for this bug report, at which point grub2 installed successfully. I presume this is due to the device.map that the postinst of grub caused to be created:

  root@ubuntu:/# cat boot/grub/device.map
  (hd0) /dev/sda
  (hd1) /dev/sdb
  (hd2) /dev/sdc

So I guess that md support with grub2 isn't quite there yet :)

Iain

ProblemType: Bug
Architecture: amd64
Date: Fri Feb 26 19:48:54 2010
DistroRelease: Ubuntu 10.04
LiveMediaBuild: Ubuntu 10.04 "Lucid Lynx" - Alpha amd64 (20100215)
Package: ubiquity 2.1.19
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
SourcePackage: ubiquity
Uname: Linux 2.6.32-13-generic x86_64

[Thomas (t.c)]

I come to the same error when I try to install a system with debootstrap. After debootstrap I mount /proc, /dev and /sys and chroot in the system (like there https://wiki.ubuntu.com/Grub2#Recover%20Grub%202%20via%20LiveCD).

than:

root@rescue:/# grub-install --recheck --no-floppy --modules="mdraid raid" /dev/sda1
/usr/sbin/grub-probe: error: no mapping exists for `md1'.
/usr/sbin/grub-probe: error: no mapping exists for `md1'.
/usr/sbin/grub-probe: error: no mapping exists for `md1'.
You attempted a cross-disk install, but the filesystem containing /boot/grub does not support UUIDs.

Any Help there?

[Thomas (t.c)]

root@rescue:/# blkid
/dev/loop0: UUID="b601a4fe-f75d-4d3c-a105-19f996fd06db" TYPE="ext2"
/dev/md0: UUID="79ddbf16-283c-429e-9115-3ac15a1860d8" TYPE="swap"
/dev/sda1: UUID="4dae1f16-a3e1-72ea-776c-2c25004bd7b2" TYPE="linux_raid_member"
/dev/sda2: UUID="5767efcf-bd75-9344-776c-2c25004bd7b2" TYPE="linux_raid_member"
/dev/sdb1: UUID="4dae1f16-a3e1-72ea-776c-2c25004bd7b2" TYPE="linux_raid_member"
/dev/sdb2: UUID="5767efcf-bd75-9344-776c-2c25004bd7b2" TYPE="linux_raid_member"
/dev/md1: UUID="d4a3304d-915b-4cdd-8050-f3bf43a3b457" TYPE="ext4"

[Thomas (t.c)]

and yes, create manually the /boot/grub/device.map fixed the problem...

[Colin Watson (cjwatson)]

I'm going to tentatively declare that I don't think the partitioned nature of the RAID matters, and hence mark this as another instance of bug 527401.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.