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VMWare and SQL memory tuning...

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  • VMWare and SQL memory tuning...

    im having a little issue... (more or less confusion)

    i have an instance of SQL running on a virtual 2003 R2. right now, the setup is pretty basic. i needed to set it up, and now im onto the tuning of the memory. a light test was alright, but as soon as i got a decent group of test users, the performance went to hell...

    the x64 instance is running fine, as SQL 64 does a good job at manipulating the memory... the x86 instance is proving to become a problem.

    my question focuses on the boot.ini switches normally used to tune an instance of SQL (the userva=xxx switch; the /PAE switch; and /3gb switch)

    so are these still aplicable in a virtual? im confused because of the ballon driver functionality... the virtual has had 4 gigs of memory dedicated, but it can use up to 8 gigs (the max my blades support)... when the OS needs it, it becomes available...

    so i have added the "userva=2966" tot eh boot.ini file, but i dont know if it has had any impact yet...

    will adding the /PAE switch to the .ini hose anything? right now i am 99.999% sure that i havent tuned the memory correctly and that is why my performance is crap... but im not sure how to implement these switches in a virtual environmet...

    am i making sense? i admit that SQL is not my strong suit, and SQL 2005 is even more foriegn.

    do any of you guys have any advice and/or knowledge on how a virtual handles the boot.ini switches?
    its easier to beg forgiveness than ask permission.
    Give karma where karma is due...

  • #2
    Re: VMWare and SQL memory tuning...

    Hi James,

    I have not experienced this issue before but I did find some discussion on the Internet about it. Here are some links that might help you out:


    Has anyone else had this issue before?

    Thanks for your post,
    David Davis - Petri Forums Moderator & Video Training Author
    Train Signal - The Global Leader in IT Video Training
    TrainSignalTraining.com - Free IT Training Products
    Personal Websites: HappyRouter.com & VMwareVideos.com

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    • #3
      Re: VMWare and SQL memory tuning...

      just to update, as this issue is ongoing...

      i added the two switches "userva=2966" and the "/3gb" to the boot.ini on monday.

      i rebooted the server and watched the perfmon. the free pte's were much higher, but i noticed no gain (or loss) in performance.

      after reading a good portion of knowledge base and tech net (i find this site to be more helpful, btw) i am going to apply a different ini configuration.

      i will disable the two previous entries and replace them with the "/PAE" switch, and assign the server 5 gigs of RAM to start. right now i have 4 dedicated with priority to that virtual, so if it wants more it can have it...

      my reasoning is maybe if i assign the 5 + the /PAE, it will lock the additional at boot and never free it up... because the /PAE switch is for more than 4 gigs..

      ill post the results after letting it run for another 24...
      its easier to beg forgiveness than ask permission.
      Give karma where karma is due...

      Comment


      • #4
        Re: VMWare and SQL memory tuning...

        You may wish to use the /PAE and the /3GB in conjunction with one another... it means that the app can use up to 3Gb contiguous space, as well as being able to address all the physical memory.


        Tom
        For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

        Anything you say will be misquoted and used against you

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        • #5
          Re: VMWare and SQL memory tuning...

          How is your testing going on this?

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          • #6
            Re: VMWare and SQL memory tuning...

            well, what i did was treat it like a real server. i enabled the /PAE switch and then rebooted.

            keep in mind it is a virtual, so i created a DRS cluster out of two blades (quad core opterons w/8gigs) and alloted all the memory and all the CPUs. then after reboot, used some monitoring tools to verify how much mem SQL was using. i saw it had somewhere in the neighborhood of 6.5 gigs, so i was happy.

            i made a change to SQL to lock page tables so that the mem was always available...


            everything is running like a champ. no problems with the software or install. the application's stored procs are another thing.
            its easier to beg forgiveness than ask permission.
            Give karma where karma is due...

            Comment


            • #7
              Re: VMWare and SQL memory tuning...

              So even though windows(x32) only sees the 4GB - SQL is actually using 6.5GB because of the VMware host having 8GB and it can ballon up to 8GB? When you use SQL to lock the memory does the vm kernel know this and not let you allocate that memory to another guest? Do you even need to use the /PAE switch? BTW, what tools did you use to see the SQL was using the 6.5GB? Sorry for all the questions but we are trying to convince our SQL/ORACLE DBA that VMWare is a good thing.

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