VMS® Tuning - Rules of Thumb

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Appendix A
AN EXAMPLE OF CHANGING SYSGEN PARAMETERS

A.1 CHANGING SYSGEN PARAMETERS

The following is an example of changing SYSGEN parameters. Since NON-DYNAMIC parameters are being changed, the USE CURRENT command must be specified. Each parameter should be shown first, and then changed.


Note

The SYSGEN parameter changes can be made either directly through the OpenVMS SYSGEN utility, or by making changes to MODPARAMS.DAT and then using AUTOGEN. For simplicity, the examples in this guide show using SYSGEN directly.

Example A-1 Changing Sysgen Parameters

                  APPLICATION SSYSTEM OpenVMS Version 5.4-2 
 
   Username:  SYSTEM 
   Password:  (the system password) 
 
  $ SET DEFAULT SYS$SYSTEM 
  $ RUN SYSGEN 
  SYSGEN>  USE CURRENT 
 
  SYSGEN>  SHOW SYSMWCNT 
  Parameter Name             Current   Default   Minimum   Maximum 
  SYSMWCNT                       800       250        40     16384 
  SYSGEN>  SET SYSMWCNT 1000 
  SYSGEN>  SHOW IRPCOUNT 
  Parameter Name             Current   Default   Minimum   Maximum 
  IRPCOUNT                       300        60         0     32768 
  SYSGEN>  SHOW PAGEDYN 
  Parameter Name             Current   Default   Minimum   Maximum 
  PAGEDYN                     300000    190000     10240        -1 
  SYSGEN>  SET PAGEDYN 500000 
      . 
      .  SHOW and SET as necessary for each required parameter 
      .     
 

A.2 CHANGING PAGE AND SWAP FILE SIZE

If the swapfiles or pagefiles are too small, use the following commands: Example A-2 Changing PAGE and SWAP File Size

 
  SYSGEN>  CREATE SWAPFILE/SIZE = value 
  SYSGEN>  CREATE PAGEFILE/SIZE = value 
 
 . 
 .  Where value = the observed required size in disk blocks 
 . 
 
  SYSGEN>  WRITE CURRENT 
  SYSGEN>  EXIT 
 
  $ log 
    SYSTEM       logged out at 01-AUG-1987 09:50:59.95