Exam SK0-005 topic 1 question 44 discussion

The RAID 6 design distributes data across a minimum of four HDDs the same way that RAID 0 and RAID 5 do, but it also distributes parity information across two disks. The result is that a RAID 6 array can recover data even with the failure of two HDDs. Reads are quick, like RAID 5, but writes are slower due to the duplication of the parity data. It is a good general solution as long as the performance hit on write tasks is not a problem for your environment. Ref. The Official CompTIA Server+ Study Guide (Exam SK0-005) page 114.

RAID 6 Disk Striping with Double Parity The RAID 6 design distributes data across a minimum of four HDDs the same way that RAID 0 and RAID 5 do, but it also distributes parity information across two disks. The result is that a RAID 6 array can recover data even with the failure of two HDDs. Reads are quick, like RAID 5, but writes are slower due to the duplication of the parity data. It is a good general solution as long as the performance hit on write tasks is not a problem for your environment. RAID 6 requires a minimum of four HDDs.