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I have a Gigabyte X85A-UD3R motherboard with an ICH10R. I also have a RAID 0 (striping) setup of 2x1TB disks, configured at the BIOS level (raid controler which boots before OS/after BIOS?) which merges the two physical volumes into one 2TB volume labelled MainVolume. The volume contains four primary partitions - two for Windows (boot and data) and two for Linux (root and swap), no logical partitions.

I had problems installing any Ubuntu after 10.04 on this setup. In fact, I installed 12.04 by installing 10.04 first and then upgrading. Ubuntu 10.04 worked flawlessly, but after upgrade to 12.04 it always displayed a message during boot in the console, something like "iwatch dm-5 failed" (not sure), but I didn't pay much attention to it because the system worked. Up until today's upgrade to 12.10.

Today when I upgraded to 12.10 at the end of the upgrade process it tried to install grub, and failed with the message:

Path `/boot/grub' is not readable by GRUB on boot. Installation is impossible. Aborting. 

Then the upgrade manager offered me to select a destination for GRUB - sda, sdb or MainVolume. When I select MainVolume it falls back to the above error message and asks again. I didn't choose sda or sdb, because I thought it might write to the physical drives as non-striped and mess up existing partitions. In the end I chose not to install grub and completed the upgrade.

I'm writing this now from that box which I don't dare to reboot since it might not boot.

:(

Any ideas & sugesstions?

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@K.KPatel: I don't see your post even mention fakeraid/dmraid... What makes you think it's a duplicate, the fact that grub-install fails? It can fail for any number of reasons. –  Boris B. Oct 23 '12 at 20:46
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6 Answers 6

up vote 3 down vote accepted

Maybe you should reinstall and update grub2? Or try boot-repair tool to fix issues. I dont know if it will work with 12.10 it worked with 12.04 just fine

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Thank you, boot repair did it (seems it did grub-install ... --force). –  Boris B. Oct 23 '12 at 20:42
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When I tried to install grub, it failed as well because it was defaulting /dev/mapper which is not an actual device.

I had to drop to BusyBox from the grub screen and ls /dev/m* showed a device called /dev/mapper/pdc_baagjii, so that's where I installed grub to, then rebooted no problem. Hope that helps you.

The install of grub failed because I wasn't certain of the device location. It was defaulting to /dev/mapper.

So I dropped to Alt+F2 and hit Enter key to enable ~BusyBox (which is the environment that the installer runs in).

I looked at mount | grep mapper output and saw that my root partion was listed as /dev/mapper/pdc_baagjii1 / ext4.

That meant my grub install location should be the device /dev/mapper/pdc_baagjii.

I flipped back to Alt+F1 to continue the installation and typed /dev/mapper/pdc_baagjii. I could also have typed grub-install /dev/mapper/pdc_baagjii.

After successfully installing grub at /dev/mapper/baagjii device location, I rebooted and was happy to see my Login prompt waiting for me.

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Can you explain in greater detail what you did? Right now it seems unlikely that anyone who doesn't already know this solution would be able to apply it. –  Eliah Kagan Jan 9 '13 at 23:52
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Yes, it seems that the distribution upgrade script does not play nice with RAID0. I had a simple fresh 12.04 install with two SSDs as a single RAID0 drive, grub installation failed in a similar manner. Booting with a USB drive and using the boot-repair tool to reinstall GRUB resolved the problem.

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had similar issue with a fresh install on 12.10 on a vertex 4. went through the whole boot repair etc

tried a reinstall, this time i added a /boot partition to the start of the drive rather than let ubuntu installer do its auto install. bingo, no problems, grub2 works and can boot into system.

hope that helps

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I had a very similar issue. I upgraded from 12.04 to 12.10 and after the install I had the same issues as you. I've spent hours messing with various things trying to get this resolved, complicated by the fact that I currently can't boot from DVD/CD and my largest functional USB key that my main board will boot is < 120mb.

Finally I went back to trying super grub2 disk again and tried booting into Ubuntu using the 3.5.0-17-generic kernel instead of the 3.2 kernel I was previously on. Earlier, I was unable to boot that kernel due to it hanging before loading completely (I can't remember what exactly caused the hang) but it finally let me boot. I was then able reinstall grub-pc & dependencies as normal. Make sure you have some way to chainload into your install on the 3.5 kernel and maybe you'll be able to reinstall grub.

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I had the same issue with a new 12.10 installation. The solution was based on the one presented by Matt, but it needed some further steps:

  • Select "something else" on the partition wizard to manually define the partitions.
  • Create at the start of the hard drive a 250 MB ext4 partition, mounted to /boot (set as primary)
  • Create the root and swap partitions
  • When the installation fails to install grub, choose to continue without installing it.

When the installation ends:

  • mount the "/boot" and "/" partitions manually
  • grub-install --boot-directory=(directory where the "/boot" partition is mounted) --root-directory=(directory where the "/" partition is mounted) (hard drive device)
  • umount the partitions
  • load "gparted", select the "/boot" partition, and activate the "boot" flag on the "manage flags" option. (Be sure to have this flag enabled, otherwhise the system won't boot).

After doing that, I was able to reboot and use the OS :)

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