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Former Member

PF usage is more than 20 GB for NW 2004s systems.

Hello All,

I have windows box which is with AMD64 processor, Available RAM is 16 GB.

I have installed two systems on it.

Systems are up and running, but in task manager it show PF usage as 21.2 GB and free physical memory as 8 GB.

I am not getting why it is using that much pagefile.

For both the system DB is Oracle.

I am following Note 88416 for Zero-Memory management. As per this note I have set PHYS_MEMSIZE for 1st system as 3 GB and for 2nd system as 4 GB. SGA_MAX_SIZE for both DB instances is 2 GB each.

If I stop one system then also PF usage it show is 14.5 GB.

So my question is why system is using so much pagefile although physical memory is free?

Previously when PHYS_MEMSIZE parameter was not maintain by us (before applying note 88416), at that time PF usage was as high as 46 GB. Total virtual memory configured is 60 GB.

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2 Answers

  • Nov 25, 2008 at 09:22 AM

    Please check if you have applied the hotfix mentioned in

    Note 1009297 - Windows Server 2003 Family: High Paging Rates

    Markus

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    Former Member
    Nov 25, 2008 at 09:51 AM

    As per Note 1009297.

    The SAP extended memory management keeps a user context in shared memory and maps the pages for a user when starting processing and unmaps them at the end of each dialog step. Windows implements the unmapping to remove the memory pages from the process and moves them into the modified page list. With Windows Server 2003 a more aggressive strategy is implemented to reduce the number of entries in the modified page list by writing the pages back to the page file.

    This means that the Page file usage should be there if System is being use. ( Correct me if I am wrong )

    But Now if I restart the system, and no one is logged in to the system, then I also I can see the PF usage as 21.5 GB.

    Is it like when system starts it require some amount of page file usage even if free space is there in physical memory?

    I have only memtioned PHYS_MEMSIZE parameter in profile and as per Note 88416 all other parameters are automatically got set. So is any specific parameter is there by which we can restrict page file usage or find why at all system is using page file when free memory is there?

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    • There is a fix for this problem which changes the algorithm to not use much of the paging file when there is enough free memory available:

      Microsoft has improved this algorithm for SAP and fixed this behavior.
      In order to get this fix contact the Microsoft Support and request KB 931308. KB 931308 is not part of the Microsoft Security Hotfix System and is only available on demand.

      So if you apply that hotfix you will see that less of the pagefile is used if there´s enough physical memory available.

      Markus