This document describes how to set up SCSI hardware RAID, focusing mainly on host-based adapters from DPT, though the principles applied here are fairly general.
Use the information below at your own risk. I disclaim all responsibility for anything you may do after reading this HOWTO. The latest version of this HOWTO will always be available at http://www.ram.org/computing/linux/dpt_raid.html.
For the purposes of this HOWTO, I am assuming you have only a Linux system running. Also, note that I've only tried this out with the DPT Smartcache IV PM2144UW and PM3334UW controllers, with DPT (SmartRAID tower) and Wetex enclosures, and I have no experience with other setups. So things may be different for your setup.