Compaq StorageWorks HSZ80 Configuration And Cli Reference Manual page 143

Large chunk sizes also tend to increase the performance of random reads and writes.
It is recommended that you use a chunk size of 10 to 20 times the average request
size, rounded up to the nearest multiple of 64. In general, a chunk size of 256 works
®
well for UNIX systems; 128 works well for OpenVMS™ systems.
Increasing the Data Transfer Rate
A small chunk size relative to the average request size increases the data transfer rate
by allowing multiple disk drives to participate in one I/O request. This concept is
shown in Figure 3–16.
Request A
Figure 3–16. Chunk Size Smaller than the Request Size
Applications such as CAD, image processing, data collection and reduction, and
sequential file processing tend to require high data-transfer rates.
Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide
Chunk size = 128k (256 blocks)
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A
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A
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