Raid 6 logical drives, Id 6 (see, Appendix d: understanding raid – Adaptec Storage Manager User Manual

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Appendix D: Understanding RAID

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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

400 GB

Disk 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 & P2)

Not Used

500

449

...

Unused Space: 150 GB

Drive Segment Size (Smallest Disk Drive)