"This guide explains how to set up software RAID1 on an already running LVM system (Debian Etch). The GRUB bootloader will be configured in such a way that the system will still be able to boot if one of the hard drives fails (no matter which one)...
"In this tutorial I'm using a Debian Etch system with two hard drives, /dev/sda and /dev/sdb which are identical in size. /dev/sdb is currently unused, and /dev/sda has the following partitions..."