RAID 6 PCI controllers

RAID 6

— recording format similar to RAID 5 (see the relevant paragraph), but with two checksums, recorded on two separate disks. This improves resiliency—the array remains available if any two drives fail—but reduces performance even further. A RAID 6 array requires at least 4 drives, and the total capacity is equal to the sum of the capacity of all drives minus the capacity of the two drives.