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About RAID 5
A RAID 5 configuration features the data striping of RAID 0, combined with the parity benefits
of RAID 4. Using a parity (exclusive OR) function, RAID 5 can tolerate the loss of one drive.
Parity information is distributed across all drives rather than being concentrated on a single
disk. This avoids throughput loss due to contention for the parity drive. Spare drives can be
used to rebuild an array after a drive is replaced.
RAID-5 capacity equals the size of drive times (number of drives -1). In addition, the array's
storage efficiency increases with the number of disks; from 66.7 % for 3 drives to 75 % for four
drives: storage efficiency = (number of drives -1) X (number of drives).
RAID Level 5:
"Independent Access Array with Rotating Parity"
High Data Reliability & Transfer Capacity
Improved Write Performance
The server uses new designs to improve RAID-5 write performance for both large sequential
and small random transactions. This advanced block caching firmware delivers extremely high
performance for RAID-5 write operations.
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Disk Array
Controller
Array Management Software
Provides Logical to Physical Mapping
1
2
3
4
5
P
7
P
8
P
10
11
Disk 0
Disk 1
Disk 2
Figure 42: RAID 5 Array Schematic
DATA
P
6
Physical
9
12
Disk 3
MAXX-2420-EX Owner's Manual
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