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OpenVMS System Tuning? (QUANTUM)

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The Question is:

Is the scheduler, e.g. the usage of quantum/iota significantly changed in
 AXP/VMS V7.2 compared to VAX/VMS 6.2....?
It can be demonstrated, that the dynamics of OpenVMS are completely different
the "old times". If there is only ONE compute bound job (prio=4) without any
 i/o or
paging on the system (DS10), then the behavior of the system is extreme
 sluggish, e.g. mc sysgen show quantum does take 40 seconds in a second
 decterm? (quantum is 10, iota=1).
I did encounter the same kind of problems on axp 4100 multiple cpu mashines,
 but never had a chance, to track the user (stock traders) complaints in any
 way, so we had been having this kind of non-traceble problem for more than 2
 years, most of the time,
the extra cpu's on the 4100's did circumvent the problem.

The Answer is :

  It can be demonstrated that OpenVMS has changed significantly from
  "old times" in a variety of ways.  Old rules-of-thumb and older
  tuning techniques may or may not be applicable to newer OpenVMS
  releases and/or to particular OpenVMS VAX or OpenVMS Alpha systems.
  As for one discussion of a change related to the processing around
  QUANTUM, please see topic 4341 here in Ask The Wizard.
  The value of IOTA defaults to 2, and changes to it generally also
  involve a (recommended) discussion with Compaq Customer Services.
  Without significantly more information on the system configuration
  (hardware, software, settings, etc), the OpenVMS Wizard is not in a
  position to assist with tuning and site- and configuration-specific
  issues.  Please contact the Compaq Customer Support Center directly
  for assistance in tuning the system, and for assistance meeting the
  particular system responsiveness requirements.

answer written or last revised on ( 30-MAY-2000 )

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