RAID 6: Independent Data disks with two independent distributed parity schemes

Characteristics/Advantages

1. RAID 6 is essentially an extension of RAID level 5 which allows for additional fault tolerance by using a second independent distributed parity scheme (two-dimensional parity)

2. Data is striped on a block level across a set of drives, just like in RAID 5, and a second set of parity is calculated and written across all the drives; RAID 6 provides for an extremely high data fault tolerance and can sustain multiple simultaneous drive failures

3. Perfect solution for mission critical applications

Disadvantages

1. Very complex controller design

2. Controller overhead to compute parity addresses is extremely high

3. Very poor write performance

4. Requires N+2 drives to implement because of two-dimensional parity scheme