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Paging and Performance?

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The Question is:

I am experiencing a typical problem on OpenVMS 7.1 running on MicroVAX 4000
 system with 64 MB physical memory. The problem is a follows.
I have a application called DMS (Design Management System) that uses Ingres a
 backend database. I am experiencing a very high rate of page fault(137
 /Transaction) on this particular process, when the same set of commands are
 executed on another system wit
h same set of configuration the page fault rate is very minimum (10 Page
 Faults/Transaction), could you please tell me why there is a difference ?, I
 have tried chaning the system parameters and now it exactly matches with the
 system where page falut rate
 is low, but still the problem exist and the page fault rate has not come down
 ?, it will be a great help if you can suggest me how to reduce the page fault
 rate on this system
I am giving the system configuration below.
MicroVAX 4000
OpenVMS VAX 7.1
Ingres 6.

The Answer is :

  First, determine if there is actually a problem here, and determine
  the specific nature of the problem.  For instance, on a system
  such as this, 137 soft faults is not excessive.  (It would also point
  to the use of the modified list...)  Also, please note that 64 MB is
  a relatively small amount of physical memory, and having sufficient
  physical memory (for working sets, for I/O caches, and for general
  use) can solve a number of performance problems.
  It would initially appear that you need more physical memory, or you
  need a larger process working set, or a larger WSMAX setting.
  Please see the performance management documentation available in the
  OpenVMS manual set for a procedure intended to locate the cause of
  the problem (excessive faulting), and to resolve it.  This includes
  use of AUTOGEN, evaluation of process quotas and system parameter
  settings, hardware upgrades, and the use of INSTALL and other OpenVMS
  tools that can reduce memory requirements.

answer written or last revised on ( 19-JAN-2001 )

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