HP StorageWorks 1000 Modular Smart Array - Manual (Page 49)

HP StorageWorks 1000/1500 Modular Smart Array Command Line Interface user guide 49
Figure 8 RAID 6 array, with four physical hard drives (D1, D2, D3, and D4) showing distributed parity
information (Px,y)(Qx,y)
This method is most useful when data loss is unacceptable, but cost is also an important factor. The
probability that data loss will occur when arrays are configured with RAID 6 is less than when they are
configured with RAID 5.
Table 6 RAID 6 features
Advantages Disadvantages
High read performance. Relatively low write performance (lower than RAID
5), because of the need to create two sets of parity
data.
High data availability—Any two drives can fail
without loss of critical data.
More drive capacity is usable than with RAID
1+0—Parity information requires only the storage
equivalent to two physical drives.
B1
B3
P5,6
Q7,8
D1 D2 D3 D4
B2
B7
P3,4
Q5,6 B5
B8
P1,2
Q3,4 B4
B6
P7,8
Q1,2
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