VSAM Tuning

Sandeep D. Patil · New User Joined: 29 Jun 2008 Posts: 23 Location: mumbai

Hi ,
I am doing a performance tuning of a VSAM files. I would like to know what all parameters are there by which we can reduce the cost of using the VSAM files.

What are the calculation/formulae for calculating the BUFNI & BUFND parameters?

Will it be an overkill/harm if there are too many VSAM files in a particular step and we use all parameters?

Please help me in find all these parameters and various formulae...

Thanks

Anuj Dhawan · Posted: Mon Jun 22, 2009 10:59 am

Please learn to search the Forum:

www.ibmmainframes.com/viewtopic.php?t=39690&highlight=vsam
www.ibmmainframes.com/viewtopic.php?t=39682&highlight=vsam

Sandeep D. Patil · New User Joined: 29 Jun 2008 Posts: 23 Location: mumbai

Hi
Thanks for those links, but all my doubts were not been cleared using those link.
COuld you just look at the questions once again and please help me fine tuning the VSAM files.

Regards

expat · Posted: Mon Jun 22, 2009 2:07 pm

Click HERE to read VSAM Demystified.

Robert Sample · Posted: Mon Jun 22, 2009 4:48 pm

Calculating BUFND and BUFNI depends upon how you're using the VSAM file, whether it is NSR, RLS, LSR, GSR, and there's rules of thumb but I don't believe there are hard and fast calculations to use. As expat said, the Redbook will tell you what you need to know.

Will there be harm in having too many VSAM files in a step? That depends. Are the files just in the JCL, or are they opened? If they are opened, then you can definitely have problems with running out of memory.