SATA and IDE/ATA Hard Disk Drive Mirroring
I have used Promise http://www.promise.comcontrollers in the past for NetWare 3, NetWare 4, Windows 2000 Server and Windows 2003 servers. They have proven successful for two system crashes - I.E. we got the data back with little or no downtime, and were able to replace the hardware at our convenience, and with no data loss. Some IT workers shy away from Promise controllers, but others swear by them.

It looks like 3Ware http://www.3ware.com and LSI logichttp://www.lsilogic.com are players in this market as well. These controllers approach what a SCSI Raid controller costs, so for a server with fewer than 3 users, I think Promise is fine. I have one server (small to moderate load) with an IDE controller with around 20 users with no performance problems. Remember that you need to verify the status of your mirrored drive array on a periodic basis.