RAID 0
=> Use if you want good read and write performance
=> Strips data across multiple disks
=> No Fault tolerance
=> Good for Workstation computers or application which needs fast disk I/O
=> Minimum requirement: 2 hard disk

RAID 1
=> Use for mirroring (hard disk to hard disk or partition to partition )
=> Fault tolerance
=> Use this if you want exact copies of data
=> Minimum requirement: 2 hard disks

RAID 5
=> Use for dedicated FILE/App server
=> Combination of RAID 0 and RAID 1
=> Read rate high
=> Write rate medium
=> Use this for database, Internet servers (such as web, mail etc), File server etc
=> Minimum requirement: 3 hard disks

Hope this helps. Wikipdia has nice information http://en.wikipedia.org/wiki/Redunda...ependent_disks