10.04 alternate install creates unbootable system

[Hadmut Danisch]

Hi,

I just tried to install 10.04 (AMD64) with the alternate install disk on a system with two 2TB disks (WD 20EARS), trying to do as usual:

- a boot partition mounted under /boot (around 300MB) with ext4 on a raid1 consisting of /dev/sda1 and /dev/sdb1
- a main partition mounted under / with ext4 on an LVM partition on a raid1 consisting of /dev/sda2 and /dev/sdb2

(I'm using this method for years without problems, but for the first time with such large disks, I just got them yesterday)

but now the process of installing grub onto these disks failed without precise error message. The install disk just reported the system to be unbootable.

Booting the system with the desktop system and trying to install grub manually showed the problem:

Because of the disk size the installer CD had automatically chosen a GPT partition table, on which grub does not find it's place to embed itself. If then the boot partition is on a raid device, grub2 can't install itself.

grub-setup gives the error messages:

warn: This GPT partition label has no BIOS Boot Partition; embedding won't be possible!.
error: embedding is not possible, but this is required when the root device is on a RAID array or LVM volume.

[Hadmut Danisch (hadmut)]

Solution:

See

http://www.ibm.com/developerworks/linux/library/l-gpt/
http://grub.enbug.org/BIOS_Boot_Partition

I had to completely repartition the disk: Zero both disks, repeat the installation procedure as describe above, but create an additional small (128kb ... 1 MB) first and unused (!) partition on both disks. Then from the command line use parted to set the
bios_grub flag as described under http://grub.enbug.org/BIOS_Boot_Partition for both disks:

  $ sudo parted /dev/sda set <partition_number> bios_grub on

Then grub 2 can be installed as usually (and puts itself into this unused partition)

[Philip Muškovac (yofel)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage. I have classified this bug as a bug in grub2.

When reporting bugs in the future please use apport, either via the appropriate application's "Help -> Report a Problem" menu or using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.