
Advanced Technology and Systems Co., Ltd.
4
1.2.3
RAID Level 5
In RAID Level 5, parity data is generated and stored on the equivalent of one drive. If one drive fails,
the lost data can be reconstructed using data recorded on the other drives and the parity data. Parity
data is written on all of the drives in order to avoid performance degradation due to the intensive
access requirements that would result from using a single or specific parity drive.
The effective storage capacity of this RAID level is as follows:
(Effective storage capacity) = (Capacity of one drive) x (Number of drives - 1)
This RAID level is most appropriate when data protection is the primary consideration.
BLOCK 0
BLOCK 1
BLOCK 2
PARITY 0 - 2
3
4
5
PARITY 3 - 5
6
7
8
PARITY 6 - 8
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BLOCK 0
BLOCK 1
BLOCK 2
PARITY 0-2
4
5
PARITY 3-5
3
8
PARITY 6-8
6
7
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°
°
°
°
°
°
°
°
°
°
°
°
°
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°
DRIVE 1 DRIVE 2
DRIVE 3 DRIVE 4
0
4
8
°
°
1
5
P
°
°
2
P
6
°
°
P
3
7
°
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