HP StorageWorks 1000 Modular Smart Array - Manual (Page 47)

HP StorageWorks 1000/1500 Modular Smart Array Command Line Interface user guide 47
RAID 0—No fault tolerance
A RAID 0 configuration ( Figure 3 ) provides no protection against data loss when a drive fails. However, it
is useful for rapid storage of large amounts of non-critical data (for printing or image editing, for example),
or when cost is the most important consideration.
RAID 1+0—Drive mirroring
In a RAID 1+0 configuration, data on a physical hard drive is duplicated to a second drive.
NOTE: When only two hard drives are included in the array, this fault-tolerance method is called RAID 1.
When more than two hard drives are included in the array, this fault-tolerance method is called RAID 1+0.
RAID 1 is not supported on the MSA1510i storage system.
Figure 5 RAID 1 array, with two physical hard drives (D1 and D2)
When the array has more than two physical drives, drives are mirrored in pairs ( Figure 6 ).
Figure 6 RAID 1+0 array, with eight physical hard drives (D1 through D8)
Table 3 RAID 0 features
Advantages Disadvantages
Highest write performance of all RAID methods. All data on the logical drive is lost if a physical
drive fails.
Lowest cost per unit of stored data of all RAID
methods.
Cannot use an online spare.
All drive capacity is used to store data (none is
needed for fault tolerance).
Can only preserve data by backing it up to
external drives.
D1 D2
B1
B2
B3
B4
B1
B2
B3
B4
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S1
S2
S1
S2
D1
D5
B5
B1
B1
B5
D2
D6
B6
B2
B2
B6
D3
D7
B7
B3
B3
B7
D4
D8
B8
B4
B4
B8
15315