Download Compaq HSG80 - StorageWorks RAID Array Controller Specifications

4–43
Initialize Switches
You can enable the following kinds of switches to affect the format of a disk drive or
storageset:
■
Chunk size (for stripesets and RAIDsets only)
■
Save configuration
■
Destroy/Nodestroy
After you initialize the storageset or disk drive, you cannot change these switches
without reinitializing the storageset or disk drive.
Chunk Size
Specify a chunk size to control the stripesize used for RAIDsets and stripesets:
■
CHUNKSIZE=DEFAULT lets the controller set the chunk size based on the
number of disk drives (d) in a stripeset or RAIDset. If d < 9 then chunk size =
256. If d > 9 then chunk size = 128.
■
CHUNKSIZE=n lets you specify a chunk size in blocks. The relationship
between chunk size and request size determines whether striping increases the
request rate or the data-transfer rate.
See “INITIALIZE,” page 7–62 for more information on setting the Chunk Size.
IMPORTANT: While a storageset may be initialized with a user-selected chunk
size, it is recommended that only the default value be used. The default value is
chosen to produce optimal performance for a wide variety of loads. The use of a
chunk size less than 128 blocks (64K) is strongly discouraged. There are
almost no customer loads for which small chunk sizes are of value and, in almost
all cases, selecting a small chunk size will severely degrade the performance of
the storageset and the controller as a whole. Use of a small chunk size on any
storageset can result in severe degradation of overall system performance.
Compaq HSG80 Array Controller ACS Version 8.4 Configuration and CLI Reference Guide