Microsemi Adaptec ASR-8405E - RAID 6 Arrays; RAID 60 Arrays

B.9 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.
Unused Space = 150 GB
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
250 GB
250 GB
400 GB
400 GB
Drive Segment Size
(Smallest Disk Drive)
Disk Drive 2
Disk Drive 3
Disk Drive 4
Disk Drive 1
Unused Space = 150 GB
Disk Drives in Logical Drive
Based on the drive segment sizes used:
(P1 & P2)
RAID 6 Logical Drive = 500 GB plus parity
P21 P1 . . .
4492 P2 . . .
P1P1 3 . . .
500P2 4 . . .
B.10 RAID 60 Arrays
Similar to a RAID 50 array (see RAID 50 ArraysRAID RAID 50arrays RAID 50), a RAID 60 array—also known
as dual drive failure protection—is built from eight disk drives congured 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.
55
Microsemi Proprietary and Condential. Installation and User's Guide Revision 5
Understanding RAID