What You'll Need
To create a RAID 1 setup, you need a RAID controller. I decided to go with the Adaptec ATA RAID 1200A, which is an entry-level ATA/100 RAID controller that supports RAID 0, RAID 1, and RAID 0/1. You can pick up an Adaptec ATA RAID 1200A from your local computer retailer for about $50.
To create a RAID 1 setup, you need to have two hard drives. Adaptec suggests that you use identical hard drives of the same model and size.