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VSAM Tuning

 
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Sandeep D. Patil

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Joined: 29 Jun 2008
Posts: 23
Location: mumbai

PostPosted: Mon Jun 22, 2009 10:13 am    Post subject: VSAM Tuning
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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
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Anuj Dhawan

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Joined: 22 Apr 2006
Posts: 6258
Location: Mumbai, India

PostPosted: Mon Jun 22, 2009 10:59 am    Post subject:
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Please learn to search the Forum:

http://www.ibmmainframes.com/viewtopic.php?t=39690&highlight=vsam
http://www.ibmmainframes.com/viewtopic.php?t=39682&highlight=vsam
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Sandeep D. Patil

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Joined: 29 Jun 2008
Posts: 23
Location: mumbai

PostPosted: Mon Jun 22, 2009 1:37 pm    Post subject: Reply to: VSAM Tuning
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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
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expat

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Joined: 14 Mar 2007
Posts: 8593
Location: Back in jolly old England

PostPosted: Mon Jun 22, 2009 2:07 pm    Post subject:
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Click HERE to read VSAM Demystified.
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Robert Sample

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Joined: 06 Jun 2008
Posts: 8165
Location: East Dubuque, Illinois, USA

PostPosted: Mon Jun 22, 2009 4:48 pm    Post subject:
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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.
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