Adaptec DuraStor 7220SS User Manual page 135

Adaptec Storage Manager Pro for DuraStor User's Guide
Drive 1
Partition A1
Partition A2
4 GB
4 GB
Chunks
Chunks
1,P*,7,10,13...
2,4,P*,11,14...
*P = Parity
Figure A-8 RAID 5 set
Applications Suitable for RAID 5 Sets
The types of applications suitable for RAID 5 sets are the same as
those for RAID 4. The advantage of RAID 5 is the distributed
parity, thus eliminating the potential bottleneck of a dedicated
parity disk drive.
Transaction read requests are high.
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Data availability is worth protecting, but the cost of mirroring is
I
excessive.
There is a small percentage of writes in the I/O load, such as
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inquiry-type transaction processing, group office automation,
and online customer service departments.
A-16
Drive 2 Drive 3
Partition A3
4 GB
Chunks
3,5,8,P*,15...
RAID 5 Set A
12 GB
Chunks 1,2,3,4,5,6,7,8,
9,10,11,12,13,14,15...
Drive 4
Free Space
Partition A4
4 GB
Chunks
P*,6,9,12,P*...