H3C UniServer B5700 G3, User Manual

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4
Fault tolerance methods
RAID 0
RAID 0 does not support fault tolerance. As shown in Figure 5 , RAID 0 configuration provides data
striping, but there is no protection against data loss when a drive fails.
Figure 5 RAID 0
Application scenarios
RAID 0 is useful for rapid storage of large amounts of noncritical data (for printing or image editing,
for example) or when cost is the most important consideration.
Advantages
•
Has the highest write performance among all RAID methods.
•
Has the lowest cost per unit of stored data among all RAID methods.
•
All drive capacity is used to store data (none needed for fault tolerance).
Disadvantages
•
All data on the logical drive is lost if a physical drive fails.
•
Cannot use an online spare.
•
Can only preserve data by backing it up to external drives.
RAID 1
RAID 1 is also called drive mirroring. As shown in Figure 6 , P1 and P2 represent two physical drives,
and they form a logical drive. Each data block is duplicated to a second drive and saved on two
drives.