Creating a software RAID array on an already installed Ubuntu 11.04

Let's say you got confused by a misleading fake-RAID feature on an HP Blade server and you decided to ignore that the Ubuntu installer was telling you it found 2 disks while it was supposed (if it was actual hardware RAID) to be detecting only one. And let's say you are lucky to have 3 disks, and you only one to use two as the RAID array (and they do not contain your operating system, i.e. the / partition). You might wonder: "And now what? S**** you, HP!" (that last bit is if you left panic get you, of course).

HOWTO Install GRUB on several disks

This article was first written in November 2005 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/297).
To install GRUB on several disks in the same machine (for example for Software RAID setups), just issue the following commands:
#grub --device-map=/boot/grub/device.map

>> root (hd0,0)
>> setup (hd0)
>> root (hd1,0)
>> setup (hd1)
>> quit