Database Raid Selection

If this is an OLTP (Online Transaction Processing) database primarily for handling very high speed queries, use RAID level 1+0
If this is a non-critical development or staging system, use RAID level 5
If this is a non-critical OLAP (Online Analytic Processing) reporting system, use RAID level 5
If this is a critical OLAP reporting system, use RAID level 6
If this is a long-term storage OLAP warehouse, use RAID level 6