HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Command Line Interface Reference Guide (EK-G80CL-RA. C01, March 2005)

CLI Command Descriptions
142 HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software
Command Line Interface Reference Guide
CHUNKSIZE=DEFAULT (default)
CHUNKSIZE=n
Specifies the block chunk size to be used for RAIDsets and stripesets. Specify
the chunk block size by entering CHUNKSIZE=n, or allow the controller to
set the chunk size by entering CHUNKSIZE=DEFAULT.
Note: The CHUNKSIZE switch is only valid with stripesets and RAIDsets.
The default chunk size for storagesets with less than or equal to nine members
is 256 blocks or 128 kilobytes (K). The default chunk size for storagesets with
more than nine members is 128 blocks or 64 K. HP does not recommend a
chunk size less than 128 blocks (64 K).
Note: The system automatically rounds specified chunk sizes for all newly created
containers up to the next block size that is divisible by 8. This automated feature helps
to minimize performance issues and enhance controller performance. This feature
applies to only those containers created
after the installation of ACS V8.8- x .
Note: The default chunk size should be used with caution. It is imperative that you
analyze the I/O transfers being used with your application to determine the proper
chunk size. An improper value used as a chunk size can cause serious performance
problems with the subsystem.
Refer to the detailed description of chunk size that is contained in the
controller installation and configuration guide for information regarding
recommended chunk size settings for this application.