Adaptec Storage Manager - RAID 6 Logical Drives

Appendix D: Understanding RAID ● 171
RAID 6 Logical Drives
Note: RAID 1E is an upgrade feature; if the RAID 1E feature is locked,
see Adding Enhanced Features on page 21 for information on
purchasing a feature key.
A RAID 6 logical drive is similar to a RAID 5 logical drive because it
uses data striping and parity data to provide redundancy. However,
RAID 6 logical drives include two independent sets of parity data
instead of one. Both sets of parity data are striped separately across all
disk drives in the logical drive.
RAID 6 logical drives 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
logical drives).
RAID 6 logical drives must be built from four or more disk drives, to a
maximum of sixteen. Maximum stripe size depends on the number of
disk drives in the logical drive.
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
250 GB
250 GB
400 GB
400 GB
D
isk Drives in Logical Drive
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
RAID 6 Logical Drive = 500 GB plus Parity (P1 & P
2)
1
2
P1
P2
Not Used
Not Used
P1
P2
3
4 500
P1
449
P2...
...
...
...
Unused Space: 150 GB
Unused Space: 150 GB
Drive Segment Size (Smallest Disk Drive)