HP Array Controller HSG V8.7 Software - Manual (Page 126)

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the other disk drives in the storageset are available to handle other
requests. Thus, in principle, separate I/O requests can be handled in
parallel, thereby increasing the request rate. This concept is shown in
Figure 3–18.
Figure 3–18 Chunk Size Larger than the Request Size
Applications such as interactive transaction processing, office
automation, and file services for general timesharing tend to require
high I/O request rates.
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.
CXO-5135A-MC
Chunk size = 128k (256 blocks) Request A
Request B
Request C
Request D