> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On
> Behalf Of David Speake
> Sent: Monday, March 02, 2009 6:29 PM
> To: IBM-MAIN@bama.ua.edu
> Subject: VSAM BLSR
> 
> I have a customer with what they perceive as a memory problem,
Reviewing
> their JCL I feel otherwise. There are some VSAM  BLSR  values that I
> seriously question. I have written a response but am now having
insecurity
> issues - its been a while and although  "VSAM Demystified" and "DFSMS
> Using Data Sets" seem to confirm most of my material, I'd sure like to
> see a z/OS R1.9 VSAM PLM for a few hours.
> 
> I have my beach towel handy in case the egg on my face get real deep.
> Comments and pointers appreciated.

I would agree that the BUFSI/BUFSD specifications do not appear to be
helpful.  I can't confirm if there would in fact be wasted memory, but
my question to the customer would be, "Why specify BUFSI/BUFSD at all?
Why not let the system use the actual values for the buffer sizes as it
finds them?".  Especially because they are, in fact, the same for both
files.

I can confirm that the BUFND specifications are in fact cumulative.
When we first implemented a huge application with BLSR in the OS390
days, we had to be careful that for all SHRPOOL's added together, all
the BUFND's times BUFSD did not exceed the 2GiB region limit.  This was
for RRDS's, so no BUFNI was involved, though I would assume the same is
true for BUFNI as for BUFND.

HTH

Peter


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