Compaq HSZ80 manual Increasing the Data Transfer Rate, Chunk Size Smaller than the Request Size

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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.

Chunk size = 128k (256 blocks)

	A1
Request A	A2
	A3
	A4

CXO-5172A-MC

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