Cannot boot from software RAID with 2TB disks

[Matthias Brennwald]

Dear all

I just installed Ubuntu 10.04 to a RAID-5 array (md/software array with 4 x 2TB plus 1 x 2TB spare disk, so 6TB in total). I followed the instructions here:
https://help.ubuntu.com/community/Installation/SoftwareRAID

However, the installer could not install GRUB. I finished the installation without installing GRUB and then rebooted from the installer CD (alternate) and chose to "repair a broken system" and then ran a shell with /dev/md1 as my root system. Then, I did this (again, according to the documentation mentioned above):

grub-install /dev/sda    ---> this worked with not errors
grub-install /dev/sdb    ---> this did not work, there were two messages from grub-setup:

		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.


I have no clue what this is all about, so i entered the above warning to Google and found the following:
https://bugs.launchpad.net/ubuntu/+source/partman-base/+bug/506670

What are my options? I'd appreciate any hints and help on how I can make this install work.


Matthias


----
Matthias Brennwald
Eawag, CH-8600 Dübendorf
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matthias.brennwald at eawag.ch