ACCPTHSIZ perfomance - *MAX1TB vs *MAX4GB

[prumschlag@xxxxxxxxxx]

I found this in the Archives, and I am looking for futher detail.  The IBM
Redbook "AS/400 Availability and Recovery..." recommends all logicals related to
a physical should be 1TB or 4GB, but do not mix them.  It refers to performance
issues if you mix them, but it is not clear if they are referring to overall
performance, or performance in a specific program.  Anyone have any success
stories  with this?  I need to resolve a serious (2 minute) response time issue.

Phil



   
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   Subject: Re: CISC to RISC and Excessive Logical I/O
   From: "Mark Phippard" <MarkP@xxxxxxxxxxxxxxx>
   Date: Wed, 20 Jun 2001 10:31:48 -0400

   
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   Tom,

   Do a DSPFD on the PF and all of its associated LF's and look at the Access
   Path Size (ACCPTHSIZ) parameter.  If the PF and LF's do not have the same
   value in this field, it can cause performance problems.  For best
   performance, IBM recommends you change the value to *MAX1TB on all files.

   Maybe the PF came over with *MAX4GB and the LF's have been created on the
   RISC box with the new default of *MAX1TB?

   Hope this helps.

   Mark Phippard