User's Manual

44 Understanding RAID Concepts
Figure 3-5. RAID 6
RAID 6 Characteristics:
•Groups n disks as one large virtual disk with a capacity of ( n -2) disks.
• Redundant information (parity) is alternately stored on all disks.
• The virtual disk remains functional with up to two disk failures. The data
is reconstructed from the surviving disks.
• Better read performance, but slower write performance.
• Increased redundancy for protection of data.
• Two disks per span are required for parity. RAID 6 is more expensive in
terms of disk space.