Accusys ExaSAN SWF16 - Manual (Page 100)

RAID Overview
User Guide 5-3
RAID 6 is no more space inefficient than RAID 5 with a hot spare drive when used with a
small number of drives, but as arrays become bigger and have more drives the loss in
storage capacity becomes less important and the probability of data loss is greater.
RAID 6 provides protection against data loss during an array rebuild, when a second
drive is lost, a bad block read is encountered, or when a human operator accidentally
removes and replaces the wrong disk drive when attempting to replace a failed drive.
5.3.5 RAID 0+1: Striped set with Mirroring
RAID 0+1 combines the advantages of RAID 0 and RAID 1 with none of the
disadvantages. RAID 0+1 creates a mirror of the primary striped set. RAID 0+1 provides
optimal speed and reliability.