Raid 6 Arrays; Raid 60 Arrays - Adaptec ASR-6805Q User Manual

RAID 6 Arrays

A RAID 6 array—also known as dual drive failure protection—is similar to a RAID 5 array because it uses
data striping and parity data to provide redundancy. However, RAID 6 arrays include two independent
sets of parity data instead of one. Both sets of parity data are striped separately across all disk drives
in the array.
RAID 6 arrays provide extra protection for your data because they can recover from two simultaneous
disk drive failures. However, the extra parity calculation slows performance (compared to RAID 5 arrays).
RAID 6 arrays must be built from at least four disk drives. Maximum stripe size depends on the number
of disk drives in the array.
Disk Drive 1 250 GB
Disk Drive 2 250 GB
Disk Drive 3 400 GB
Disk Drive 4 400 GB
Disk Drives in Logical Drive

RAID 60 Arrays

Similar to a RAID 50 array (see
failure protection—is built from eight disk drives configured as two or more RAID 6 arrays, and stripes
stored data and two sets of parity data across all disk drives in both RAID 6 arrays.
Two sets of parity data provide enhanced data protection, and striping improves performance. RAID 60
arrays also provide high data transfer speeds.
Proprietary and Confidential to PMC-Sierra, Inc.
Document No.: CDP-00277-02-A Rev. A, Issue:
Serial Attached SCSI RAID Controllers Installation and User's Guide
Drive Segment Size
(Smallest Disk Drive)
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
Based on the drive segment sizes used:
RAID 6 Logical Drive = 500 GB plus parity
(P1 & P2)
RAID 50 Arrays on page 79), a RAID 60 array—also known as dual drive
1 P1 . . . P2
2 P2 . . . 449
P1 3 . . . P1
Unused Space = 150 GB
P2 4 . . . 500
Unused Space = 150 GB
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