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Scenario

Install Ubuntu 12.04LTS Server on a RAID10 with boot on a RAID1.

  • 4 - 2Tb SATA Hard Drives
  • 3 Partitions (/boot, /, and swap)
  • boot (256Mb from each disk) setup in RAID1 /dev/md0
    • partition is ext2 /dev/md0p1 should be where boot is loaded
  • swap and root partition (remaining disk space) setup in RAID10 /dev/md1
    • swap partition - 8Gb partition of RAID10, linux-swap /dev/md1p1
    • root partition - remaining space of RAID10 - GPT partition table, ext2 /dev/md1p2

We've setup our disks and RAID configurations using mdadm, fdisk, and parted while running the Ubuntu 12.04LTS Server Trial from a thumb-drive.

Installation fails at grub. I can't get past this. On one machine it fails at grub-dummy-install, and on the other it simply fails with grub. The latter of the machines has completed installation but asks to install bootloader at different location or not at all. Installer becomes unresponsive though if you choose "install at different location".

Goal

We want the OS loaded on the RAID10 but we want to make sure that if any drive fails the machine can still boot from /boot and find the OS on the RAID10.

What We Know

The alternative installer supports RAID10 configuration at installation, but does it achieve our goal without taking the same process in setting up the disks?

We know we should see our RAIDs in /dev/mapper/{array-name} but we don't, we only see control. This info I've gathered from this previous question

We followed instructions we've found here and here

What We Don't Know

  1. Is there a better way to do this and still achieve our goal?
  2. Why we're not seeing our disks in /dev/mapper/
  3. Most importantly: Why we can't install the boot-loader to our /boot partition, namely /dev/md0p1 at installation.
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You're using Linux software RAID, you shouldn't see your disks in /dev/mapper. You want to install grub on /dev/sda, /dev/sdb, /dev/sdc, etc. (the MBRs of all of your disks). I'd post this as an answer, except that I don't remember how to do that in the Ubuntu installer... –  derobert Mar 2 '13 at 18:49
    
So I shouldn't install grub on my RAID1, but on a small portion of each disk? –  frankV Mar 2 '13 at 19:18
    
You should put /boot on RAID1, but install grub on the master boot record of each disk. GRUB comes in several "stages"; the first stages are responsible for finding /boot—they go in the MBR. The rest loads from /boot (and grub2 understands RAID1, so it'll be able to find boot on raid1). –  derobert Mar 4 '13 at 19:16
    
what advantage is there to not having boot/ on the main array? –  frankV Mar 4 '13 at 22:29
    
Your main array is RAID10, not RAID1, and I'm not sure how well (if it all) grub handles RAID10. So you need two arrays. Also, its nice to have a second array for oh-#!#@ recovery purposes... –  derobert Mar 5 '13 at 18:33
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