If I setup a VirtualBox guest with two 30 GB virtual hard disks and follow the following steps, the result will be a fully functional, booting operating system:

  1. Boot Ubuntu 14.04 Server install CD

  2. At the partioner, select 'manual'.

  3. Put a single empty partition on each virtual hard disk.

  4. Select 'Configure software RAID' from 'manual' menu.

  5. Add the two virtual hard disks, each with empty partitions, to a new RAID 1 pair and select 'finish.'

  6. Select 'Guided Partitioning' from 'manual' menu.

  7. Return to guided partitioning and select 'Guided - use entire disk and setup encrypted LVM.'

  8. Install to recently created software RAID device and use entire storage available for LVM.

  9. Finish installation.

However, take the steps above, but substitute Virtualbox guest for bare metal and substitute two virtual hard disks for two zeroed 3TB SATA disks, and the result is an un-bootable system. No GRUB screen, BIOS skips the disks.

I tried every possible combination of GPT flags, still nothing.

Any thoughts on the cause?


So, the bare metal in question is a Lenovo x3100 M5 server with IBM firmware.

One hint to the problem, the Ubuntu server installer is dropping a BIOS compatible boot loader on the Virtualbox install.

On the Lenovo, it installs a uEFI GRUB, which, the Lenovo can boot as long as it is not on a mdadm RAID. If I follow the above steps on the Lenovo, minus the Ubuntu software RAID, it boots. If I configure the RAID 1 pair in the IBM firmware (c100/LSI fakeRAID), the install fails at the GRUB install.

Does not seem to be a GPT vs MBR issue since the Lenovo does boot the 3TB GPT LVM volume, as long as it is not on a RAID pair.


Your 3TB disks need GPT boot rather than MBR, so you will need to allocate a 1MB BIOS boot partition for grub to store its data.

See http://ubuntuforums.org/showthread.php?t=2248346 for the gory details (which I will try to summarise here when I get back to a decent keyboard).

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