RAID 6
is similar to RAID 5 in that data protection is achieved by writing parity
information to the physical drives in the array. With RAID 6, however,
two
sets of
parity data are used. These two sets are different, and each set occupies a capacity
equivalent to that of one of the constituent drives. The main advantage of RAID 6 is
High data availability – any two drives can fail without loss of critical data.