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11 Replies Latest reply: Mar 13, 2008 5:34 PM by 71981 RSS

Significant virtual memory paging was detected on the host operating system

71981 Newbie
Currently Being Moderated
On Windows Server 2003 64 bit with 32 GB of RAM running oracle 10g (10.2.0.3)
We are trying to do some load testing and with what would be considered a starting point minimum load of 150 users the system bogs down and OEM reports:

'Significant virtual memory paging was detected on the host operating system " so we go to SA and he tells us that he sees Oracle process only using 4GB of memory and with all other process only 12GB of RAM being actually used.

I know, USE UNIX...but this is for a customer with Windows servers

Any Windows guru's out there with idea?
  • 1. Re: Significant virtual memory paging was detected on the host operating system
    523455 Newbie
    Currently Being Moderated
    Do like this

    1.Start--->control panel----->system
    2.Click on Advanced tab
    3.In performance block you will have to click settings
    4.Now again you will find Advance tab
    5.In virtual memory choose CHANGE,here you can set the new value.

    :-)
  • 2. Re: Significant virtual memory paging was detected on the host operating system
    71981 Newbie
    Currently Being Moderated
    Yogi-

    I clicked my way into the area you described and find the value of:

    total paging file size of 49149MB for all drives...

    brings up my next question....this value is greater that the physical RAM size of 32GB, so what is the new value I would want to have? Should it be equal to the Physical RAM size? Should it be less? Should it be greater?

    Thanks for your reply!
  • 3. Re: Significant virtual memory paging was detected on the host operating sy
    EdStevens Guru
    Currently Being Moderated
    If the OP is getting 'significant virtual memory paging' it is because he is running out of physical memory and having to swap (page) it out to disk. How is adjusting the size of the virtual memory file going to relieve that?
  • 4. Re: Significant virtual memory paging was detected on the host operating system
    523455 Newbie
    Currently Being Moderated
    Please select the Recommended one .
    Generally It depends on the available space on hard disks .

    If you have space on hard disk you can increase.
  • 5. Re: Significant virtual memory paging was detected on the host operating system
    CharlesHooper Expert
    Currently Being Moderated
    On Windows Server 2003 64 bit with 32 GB of RAM
    running oracle 10g (10.2.0.3)
    We are trying to do some load testing and with what
    would be considered a starting point minimum load of
    150 users the system bogs down and OEM reports:

    'Significant virtual memory paging was detected on
    the host operating system " so we go to SA and he
    tells us that he sees Oracle process only using 4GB
    of memory and with all other process only 12GB of RAM
    being actually used.

    I know, USE UNIX...but this is for a customer with
    Windows servers

    Any Windows guru's out there with idea?
    The message may be a false alarm - even checking task manager on Windows 2003 may be misleading. On Windows 2003, the "PF Usage" statistic in task manager is not page file usage, but instead total virtual memory usage, which includes RAM and page file. Oracle Enterprise Manager, I believe, is showing the "PF Usage" statistic, and is making the assumption that this is page file usage.
    For additional analysis see the discussion in this link:
    http://groups.google.com/group/comp.databases.oracle.server/browse_thread/thread/b62c4d761cace2a6

    In the above thread, one person mentions that there is a potential bug that impacts only servers with AMD processors as the process memory approaches 4GB.

    Charles Hooper
    IT Manager/Oracle DBA
    K&M Machine-Fabricating, Inc.
  • 6. Re: Significant virtual memory paging was detected on the host operating system
    71981 Newbie
    Currently Being Moderated
    Charles-

    Thanks for joining this thread, I had reviewed the google group link you are mentioning and saw already what was there but we have Intel processor so our SA says "it (the bug) does not apply here"

    We ARE trying the suggestion in that referenced thread i.e. the "lock pages in memory" and will see what happens...

    New problem cropped up having bounced this server to effect that change we now cannot start the Agent and therefore can't get to the OEM performance features to observe any changes to what we observed earlier...

    All we can do right now is ask the user to go ahead and try his application again and see if, from his perspective, unmeasured as it is, performance has increased.
  • 7. Re: Significant virtual memory paging was detected on the host operating system
    dbtoo Explorer
    Currently Being Moderated
    Since you are at 10.2.0.3, you can run awrrpt.sql out of $ORACLE_HOME\rdbms\admin and get the reports that way until you figure out what's up with enterprise mangaler.

    http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/autostat.htm#i35176
  • 8. Re: Significant virtual memory paging was detected on the host operating system
    CharlesHooper Expert
    Currently Being Moderated
    According to the documentation, lock pages in memory is not compatible with large page support (where memory is allocated in 4MB blocks, rather than the usual 4KB), so make certain that you are not attempting to use the two parameters at the same time.

    In my test cases in the Google Groups link (which happens to be a Usenet message thread), OEM was suggesting that my server was using much more virtual memory than was permitted by the maximum size specified for the page file, and that was my reason for investigation.

    You may want to verify a setting that controls memory used for file caching. Display the network card properties, double-click "File and Printer Sharing for Microsoft Networks", and check the option that is specified. Based on my previous research and testing, "Maximize data throughput for network applications" seems to be the most appropriate selection. I had limited success with "Minimize memory used". Note that if you change this value, Windows may briefly shut down and bring back up the network card, which may disconnect any existing sessions.

    The file caching algorithm for 64 bit Windows is a bit different from that for 32 bit Windows, leading to Windows attempting to use a greater percentage of system memory for file caching (possibly most of the available memory). Operating system file caching is of limited use to the Oracle database server, so the amount of memory should be minimized. Windows is supposed to free the memory used for file caching quickly, but sometimes it is not accomplished rapidly enough, especially when copying multi-gigabyte files from one location to another (or some time after the copy completes).

    Charles Hooper
    IT Manager/Oracle DBA
    K&M Machine-Fabricating, Inc.
  • 9. Re: Significant virtual memory paging was detected on the host operating system
    CharlesHooper Expert
    Currently Being Moderated
    I believe that awrrpt.sql is part of an additional cost license that may be purchased from Oracle, and it may only be purchased for the Enterprise Edition of Oracle. The feature will work without purchasing the additional cost license, but the database keeps track of the number of times the extra cost feature was utilized, as well as the last date of the utilization. If Oracle Corp. decides to perform a license audit on the OP's site, there is a chance (maybe a good chance) that the extra cost feature usage will be checked.

    Charles Hooper
    IT Manager/Oracle DBA
    K&M Machine-Fabricating, Inc.
  • 10. Re: Significant virtual memory paging was detected on the host operating system
    71981 Newbie
    Currently Being Moderated
    Thanks dbtoo for the advice...

    I have that agent back up and running.

    The agent, that was 10.2.0.2, failed to start after a server bounce due to the recent change to daylight savings time here, I applied patch 5884103 as a band-aid fix until I get time to put the 10.2.0.3 agent on that box.
  • 11. Re: Significant virtual memory paging was detected on the host operating system
    71981 Newbie
    Currently Being Moderated
    Thanks Charles-

    I will take a look at that which you suggest,

    I'm beginnning to believe that the message I got out of OEM "Significant virtual memory paging was detected on the host operating system" WAS erroneous, we are not seeing it anymore, but we still have a performance issue. We do get some strange messsages at times - like suggestions to put index on a table that has just one row in it:-)