Configuring array read-ahead and writeback cache

Configuration

Memory Vendor

Measured

Absolute

Expected

 

and Part Number

Current

Maximum

Safe

 

 

Draw

Backup Time

Backup

 

 

 

 

Time

 

 

 

 

 

Main board only

Kingston

27.9mA

41.2 hours

20.6 hours

w/256 MB

KVR100X72C2/

 

 

 

 

256

 

 

 

 

 

 

 

 

Main board

Kingston

48.3mA

23.8 hours

11.9 hours

w/256 MB and

KVR100X72C2/

 

 

 

Coprocessor

256

 

 

 

w/256 MB

 

 

 

 

 

 

 

 

 

Normally, write-intensive operations will benefit through higher performance when writeback cache is enabled on that array. Read-intensive operations, such as a streaming server, may not benefit from writeback cache.

The writeback cache is used to optimize the write performance specific to your data patterns. In general, larger cache sizes will increase the write performance but can lower simultaneous read performance. The recommended size is 16 MB. The strategy of write operations results in a completion signal being sent to the host operating system as soon as the cache receives the data to be written. The hard drives will receive the data at a more appropriate time in order to increase controller performance.

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