H3C UniServer B5700 G3, User Manual

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Figure 16 Configuring RAID parameters
Table 3 Parameter description
Parameter Description
Virtual Drive Name
RAID array name, a case-insensitive string of letters, digits, and underscores
(_).
Virtual Drive Size Capacity for the RAID array.
Virtual Drive Size Unit Capacity unit for the RAID array.
Stripe Size Data block size for each drive.
Read Policy
Read cache policy:
•
Read Ahead —Enables read ahead capability. When this capability is
enabled, the storage controller can pre-read sequential data or
anticipate data to be requested and store the data in the cache
•
No Read Ahead —Disables read ahead capability.
Compared with the setting of the
No Read Ahead
,
Write Through
, and
Direct values, setting the Read Ahead , Write Back , and Cached values can
improve performance, but at the cost of losing data consistency.
Write Policy
Write cache policy:
•
Write Through —Enables the controller to send a data transfer
completion signal to the host when the drive subsystem has received all
data in a transaction.
•
Always Write Back —Uses the Write back policy even if the
supercapacitor of the storage controller is absent or faulty. If the server
is powered off, the controller cache loses its data because of lack of
power..
•
Write Back —Enables the controller to send a data transfer completion
signal to the host when the controller cache receives all data in a
transaction. If the supercapacitor is faulty, the
Write through policy is
used.
Access Policy
Read and write policy:
•
Read/Write
•
Read Only