HP LH4r Integrated HP NetRaid Controller Configuration Guide - Page 24

Chapter 2 RAID Overview Table 2-2. RAID Level Summary for Spanned Arrays RAID Level Also Known As Fault Tolerance Redundancy Type Hot Spare Option Disks Required: spans 2 arrays spans 3 arrays spans 4 arrays Usable Capacity Capacity Reduction Read Performance Random Write Performance Sequential Write Performance Typical Usage RAID 10 striping with mirrored arrays yes duplicate yes 4 6 8* least 50% intermediate intermediate intermediate Mostly small random writes with fault tolerance and enhanced speed RAID 30 striping with dedicated parity drives yes parity yes 6, 8, 10, 12, 14, or 16* 9, 12, or 15* 12 or 16* intermediate capacity of one disk for each array spanned fast slowest slow Mostly large serial transfers with fault tolerance and enhanced speed RAID 50 striping with distributed parity yes parity yes 6, 8, 10, 12, 14, or 16* 9, 12, or 15* 12 or 16* intermediate capacity of one disk for each array spanned fast slow slowest Mostly small, random transfers with fault tolerance and enhanced speed *The maximum number of devices depends on the number of channels and types of enclosures being used. 18