Low on Virual Memory in SBS 2003

Discussion in 'Windows Small Business Server' started by Allan C, May 9, 2006.

  1. Allan C

    Allan C Guest

    A client with SBS 2003 is receiving the message below on the server display.
    They have 3 Gb of RAM.
    The server was installed about 6 months ago.
    Although the SQL Server has been running since the first day, we only
    actually started putting transactions thru about a month ago.
    According to the client, the error message below seems to occur over the
    weekend as it is on the server display on Monday morning.
    The SQL server logs seem to be clean and I am not sure what to look for in
    the Event Viewers (or anywhere else).

    Thank you in advance.

    The message is:"
    "Your system is low on virtual memory. Windows is increasing the size of
    your virtual memory paging
    file. During this process, memory requests for some applications may be
    denied. For more information,
    see Help."
     
    Allan C, May 9, 2006
    #1
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  2. This is a normal thing. If you go to CP -> System -> Advanced tab ->
    Performance -> Advanced again, you'll see the Page File settings. If you
    have an initial size that's smaller than the maximum size, when the system
    wants to use a bigger page file than the initial setting, it'll dynamically
    increase the size of the page file, and you'll get that message.

    You can avoid that by setting the initial and maximum settings both to equal
    the recommended size indicated at the bottom of the window. This avoids a
    (probably brief and minor) performance hit while the page file is
    dynamically adjusted, and more importantly avoids page file fragmentation.
    IMO on systems with a lot of RAM this may generally not be worth bothering
    with, but if you're getting size adjustment messages frequently, I'd do it.
    Keep in mind that on a system with 3 GB RAM the recommended setting is going
    to result in 4.5 GB being dedicated to page file, so you may need to move it
    off C. Also, page file changes don't take effect until you reboot.
     
    Dave Nickason [SBS MVP], May 9, 2006
    #2
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  3. Allan C

    Allan C Guest

    Two questions:
    1. I could not see how to *move* it, just how to set the min/max size.
    2. I am worried about *why* it needs to increase the page file to begin with
    considering that we have 3 Gb of RAM and maybe only 10 concurrent users. I
    am concerned that some component of SBS is not behaving properly and
    releasing memory when it should.
     
    Allan C, May 9, 2006
    #3
  4. Allan C

    Maxibo Guest

    Hi Allan

    System low on virtual memory is a system leak somewhere. Have all updates
    applied especially Exchange and ISa ? Also SBS SP1.

    Task Manager, proccesses, tick show all proceses... does this show anything
    ?

    Have you increased the memory but not increased the paging file ?

    Just to add to Dave 1.5 calculation of RAM is correct but to a maximum of
    4096 (standard 2003 server), therefore cannot have 4.5gb, if had 4gb memory
    cannot make pagefile bigger than 4096.
     
    Maxibo, May 9, 2006
    #4
  5. Interesting. I'm not inclined to play with this on my production SBS, which
    is the only box I've got with 4 GB RAM, but it's showing a recommended page
    file size of 6142. Of course that doesn't mean it would let me set it that
    high, but logically you'd assume the system wouldn't recommend something it
    didn't allow.

    I don't think a memory leak is the only explanation for this. The system
    sets the initial size pretty low by default. If something called for a lot
    of RAM faster than Exchange could release it, that could probably trigger a
    page file size increase.
     
    Dave Nickason [SBS MVP], May 9, 2006
    #5
  6. Allan C

    Maxibo Guest

    Hi Dave, sorry I should have added another line previously...

    I too thought it was 1.5 and only found out recently, didn't think of any
    limits. Recently increased clients server to 4GB and automatically went to
    increase page file and get message when you click ' SET' about 4096..

    Go on, give it a try and increase above 4096.... ;-)... and agree with you,
    why it says something when you cant.
     
    Maxibo, May 9, 2006
    #6
  7. Allan C

    Allan C Guest

    SBS is at SP1.
    Don't know about the others.

    Task Manager is running 74 processes. Commit charge is around 1.6 Gb.
    On the performance tab, the PF usage is 1.63 Gb
    Is this the information you are looking for?
     
    Allan C, May 9, 2006
    #7
  8. Allan C

    Allan C Guest

    Hmmm...
    Am I supposed to be putting a cap on the maximum amount of RAM that Exchange
    and/or SQL is permitted to use?
    If so, where is that setting and what are reasonable maximums?
    TIA.
     
    Allan C, May 9, 2006
    #8
  9. you can go beyond 4096 by either making multiple paging files on the same
    HDD or by having multiple paging files across different partitions.

    Configuring page files for optimization and recovery in Windows Server 2003,
    in Windows 2000, and in Windows NT
    http://support.microsoft.com/kb/197379/

    (but this one took some finding)
    How to overcome 4,095-MB paging file size limit in Windows
    http://support.microsoft.com/kb/237740/en-us
     
    SuperGumby [SBS MVP], May 9, 2006
    #9
  10. Allan C

    Maxibo Guest

    Hi Allan

    I know it is not advisable to run IE on the server but I am very happy to
    just access windows updates on server to check updates. It is very good now
    as includes other components than just the OS... this will give you a list
    of outstanding updates, more importantly Exchange SP2.

    In task manager I am really looking at CPU, mainly it should show system
    Idle process at the top (click CPU column to sort in order) Is anything
    taking CPU, possibly just our luck that will be ok and need to know process
    at time of virtual memory message.... ;-(

    Exchange (store.exe) should and does hog most of memory and releases when
    other apps need it. SQL you can manipulate memory but lets not do that yet.

    Have you configure monitoring and reporting? does this show any alerts ?...
    If not do set it up as this is very cool tool.

    Checking back, you say that present page file is 2046 ??? What is
    recommended ? On an SBS box with the many different components we have, even
    with 3GB RAM, OS, SQL and Exchange will think oh 3GB RAM I should have 4,5GB
    page file (covered earlier that cant go above 4096) so SQL may say to
    Exchange, you keep your RAM Im gonna use the PF and then virtual memory
    issue..... Try increasing the page file, but how much disk space on C ?

    As Dave says could move page file to another drive... my teachings have
    been, if OS on Raid 5 then best to move page file off of it as don't need
    tolerence and can affect performance but if SQL databases on another drive
    dont want it on here...lol... many things to think about...

    In summary, check if all patches are applied... if had issues and went to
    Msoft PSS difficult to get them to trouble shoot without patches being
    applied. If many patches outstanding may need to apply in parts... let me
    know how many available... Also do increase the page file... if C drive has
    the capacity leave it here for now.
     
    Maxibo, May 9, 2006
    #10
  11. Allan C

    Maxibo Guest

    Hi SG, thanks for the links... but any comments on the virtual memory
    problem ?
     
    Maxibo, May 9, 2006
    #11
  12. OHH, please note: I am not suggesting this is either necessary or desirable
    in this particular case.
     
    SuperGumby [SBS MVP], May 9, 2006
    #12
  13. With a commit charge at around half of the available RAM, I wouldn't be
    doing anything to throttle the amount of RAM used by SQL. In no case would
    I attempt to do anything about Exchange in the absence of specific errors
    being logged by Exchange.

    If you take a look at the page file article posted by SuperGumby and tweak
    the page file a little, I think you'll be all set without looking into
    Exchange or SQL further. With the commit charge at 1.6, it sounds like
    everything is playing nicely.
     
    Dave Nickason [SBS MVP], May 9, 2006
    #13
  14. Are you sure Dave? I thought the message indicated that the system is
    increasing the page file beyond the normal maximum value. I thought change
    between the standard min and max was transparent.

    What 3rd party apps are on the box? It is not normal for a properly
    configured and patched SBS to have this error.
     
    SuperGumby [SBS MVP], May 9, 2006
    #14
  15. Allan C

    Maxibo Guest

    Good point about 3rd party apps, however dont think PF is at min recommended
     
    Maxibo, May 9, 2006
    #15
  16. I'd normally say something is misbehaving.

    A simple item to look at is the 'peak memory usage'. In Task Manager, Select
    the 'Processes' tab, View, Select Columns. You might try adding both the
    'Peak Memory usage' and 'Virtual Memory Size'. Restart the system and some
    short time after it has been running observe the list, maybe do a screen
    dump of the list sorted by each column. Come back in a couple of days and
    compare the lists. When the error occurs, compare the list again. Anything
    stick out?
     
    SuperGumby [SBS MVP], May 9, 2006
    #16
  17. BTW with 3GB RAM in the machine I'd probably set the pagefile to 0 on the OS
    partition, set to some arbitrary value on another drive (say 4GB), restart,
    defrag the OS partition, and then set min/max on the OS partition to the
    same value (4095).

    or use one of the available tools to defrag the OS partition pagefile after
    setting it to max.
    http://www.sysinternals.com/Utilities/PageDefrag.html

    I'm not sure whether pagedefrag also moves the paging file to the optimal
    area, the outside of the disk. Of course, the 0 and recreate process DOES
    NOT do this. The overall partition scheme and drive type (RAID array?) must
    also be considered. It is my belief that if the heads are scooting all over
    the disc to access other stuff anyway then the positioning of the page file
    for optimal performance is debatable.
     
    SuperGumby [SBS MVP], May 10, 2006
    #17
  18. I'm not 100% sure, but I'm pretty sure this just means the page file size
    has been increased from whatever it was at previously. I don't think the
    system can increase it above the maximum, and I'm thinking this is just to
    let you know that it's been done. It's a normal function but there's a
    performance hit involved, so you'd want to make adjustments if it happened
    frequently.

    I wonder if we're all talking about the same message. This is the one I'm
    thinking of, and it's not even a warning, it's just informational. I got
    one or two of these right after swinging to my new hardware. I ignored them
    and they stopped after all the configuration, etc. was done. They're easy
    to miss.

    Event Type: Information
    Event Source: Application Popup
    Event Category: None
    Event ID: 26
    Date: 2/28/2006
    Time: 12:52:47 PM
    User: N/A
    Computer: SBS
    Description:
    Application popup: Windows - Virtual Memory Minimum Too Low : Your system is
    low on virtual memory. Windows is increasing the size of your virtual memory
    paging file. During this process, memory requests for some applications may
    be denied. For more information, see Help.
     
    Dave Nickason [SBS MVP], May 10, 2006
    #18
  19. Allan C

    Allan C Guest

    Veritas Backup and APC PowerChute (not sure which version).
     
    Allan C, May 10, 2006
    #19
  20. Allan C

    Maxibo Guest

    Quote from Allan ' I just checked at the client and the minimum is 2046, max
    is 4092 and the
    currently allocated is 2046.'

    If server has 3GB of RAM them something isn't right here.... I have asked
    what does the server say as recommended? I am thinking it had originally a
    lower amount of ram and has been increased but the PF hasn't ???
    Alternatively faulty memory, as if 3GB installed the server should be saying
    more than 2046 as minimum ?

    If we increase the PF to minimum recomended (remembering 4096 limit), could
    this be all that is rewuired to solve the virtual memory error ?
     
    Maxibo, May 10, 2006
    #20
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