Quick steps to make a raid disk on some number (4) drives, on Ubuntu 10.04.02.

Prerequisite software installs required:
o mdadm (apt-get install mdadm)
o lvm

Install all the drives in the machine.
Partition the drives, first partition one then copy that partition table to the remainder.
o fdisk /dev/sda
- (n)ew partition
- (p)rimary
- (1)
- (t)
- (fd)
- (w)
o copy the partition table to a file for later use.
- sfdisk -d /dev/sda > /tmp/table
o copy the saved table to all remaining disks.
- for d in b c d; do sfdisk /dev/sd${d} < /tmp/table ; done

Create the raid device (raid5 across all drives in this case):
o mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1

Monitor progress of the raid device build:
o cat /prod/mdstat