How will CA Hyperbuf behave for file allocations that use BLSR? For example, if the JCL has: SUBSYS=(BLSR,?DDNAME=WK00017I?,?HBUFNI=40,BUFND=10?)

Document ID : KB000046301
Last Modified Date : 14/02/2018
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Question:

How will CA Hyper-Buf behave for file allocations that use BLSR? For example, if the JCL has: SUBSYS=(BLSR,’DDNAME=WK00017I’,’HBUFNI=40,BUFND=10’)

Answer:

AMPOVR=GREATER says that this particular OPEN will require the best buffer sizes, what is in the JCL? If the JCL is better, then the JCL statements win. 

AMPOVR=FORCE says that it does not matter what you have in your JCL, even if it is better, use CA Hyper-Buf decisions regardless. 

This option does not require a GLOBAL setting. You can specify this on a INCLUDE statement for a specific program or DD statement. 

Keep in mind you are looking at application tuning. Not system tuning. Hyper-buf can be used at a data set level, ddname level, program level, jobname level, or global level. 

When performing the tuning process with ANY VSAM tool like CA Hyper-Buf you do not simply figure one set of options fits all applications. 

Baby steps are best, especially for older applications that may not run in LSR and still may be linked in 24bit mode. Possibly, the customer does not have the source code any longer. 

Set the global parms low and then use the MODE=INCLUDE levels to be more aggressive with applications.