I have a SuperMicro box with an Areca RAID controller installed. The RAID controller is configured for RAID 6 + Hot Spare. I am attempting to install Ubuntu 12.04 LTS. I set up LVM with separate partitions for /, /var, swap, and /data. While progressing through the installer, I get repeated failures at the Grub install step: "Unable to install grub /dev/sda" -- attempting to manually specify the location where Grub should be installed (presumably /dev/mapper/vg0-root) yields a similar result.
The installation step that triggers the failure: