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  • VM Memory Confusion/Question

    Hey All,

    I am hoping someone can help me out/shed some light on an issue I am seeing. I thought I had a good understanding of memory management in ESX, but maybe not.

    A little bit on the setup. We currently are running a four node vSphere cluster (with U1). Each host has 32GB of physical memory and none of the four are currently running over a 50% memory utilization per ESX performance graphs.

    I have a Resource Pool currently configured with a limit of 36GB of memory and currently only has 26GB of it configured. There are 10 VM's running in the RP two of which are 2vCPU/w 4GB of memory and the remaining eight are 1vcpu/1 or 2GB of memory.

    So now the question, in that RP on the Resource Allocation tab is see that 7GB of memory is being consumed by the balloon driver and an additional gig is going to swap. On one particular machine it using 2.3GB of balloon, but when viewing inside the VM it says that it still has 1.5GB free. Should I be worried about the ballooning and add additional memory to the VM or the RP? Or is this a case of the driver taking memory back for the host?

    TIA,

    -Jason
    MCSA/MCSE 2K3,MCITP:ESA,MCTS x 4,VCP x 2

  • #2
    Re: VM Memory Confusion/Question

    I would start by comparing the figures in the Memory section on the Resource Allocation tab on the VM itself.

    e.g.

    myvm
    Allocated: 1024MB
    Shares: Normal
    Reservation: Not set
    Limit: Unlimited

    I have attached a screenshot of what i see within vCenter for this VM.

    Of note, nothing is ballooned or swapped. What do your figures tell you?

    Simon
    Attached Files

    Comment


    • #3
      Re: VM Memory Confusion/Question

      Simon,

      Thank you for the reply. Attached is a screen shot of the memory information from the Resource Allocation tab:

      TIA,

      -Jason
      Attached Files
      MCSA/MCSE 2K3,MCITP:ESA,MCTS x 4,VCP x 2

      Comment


      • #4
        Re: VM Memory Confusion/Question

        And how busy is that server?
        Marcel
        Technical Consultant
        Netherlands
        http://www.phetios.com
        http://blog.nessus.nl

        MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
        "No matter how secure, there is always the human factor."

        "Enjoy life today, tomorrow may never come."
        "If you're going through hell, keep going. ~Winston Churchill"

        Comment


        • #5
          Re: VM Memory Confusion/Question

          Originally posted by Dumber View Post
          And how busy is that server?
          Dumber, thank you for the reply. Actually, the server is not all that busy. One thing that I did do (and can't believe I overlooked) was upgrade the version of VMware Tools on the box. Currently the statistics look like the following.

          I will continue to watch the VM to see if it spikes up again.

          -Jason
          Attached Files
          MCSA/MCSE 2K3,MCITP:ESA,MCTS x 4,VCP x 2

          Comment


          • #6
            Re: VM Memory Confusion/Question

            Hi,, thanks for submitting the screenshots. It looks like it was down to the tools!

            What version of tools did you upgrade from and to?

            Simon

            Comment


            • #7
              Re: VM Memory Confusion/Question

              Simon, thanks for the post. Sorry I don't remember the exact version of the previous tools, but it was prior to Update 1. The current version is ver 4.0, build 236512.

              Also for some reading to share, I found the below links very informative when looking into the memory issue:

              Impact of Memory Reservation by Frank Denneman

              Memory Resource Management in VMware ESX Server by Carl A. Waldspurger

              Understanding Memory Resource Management in VMware by VMware

              -Jason
              MCSA/MCSE 2K3,MCITP:ESA,MCTS x 4,VCP x 2

              Comment


              • #8
                Re: VM Memory Confusion/Question

                Ok, thanks for the links!

                Also check out these sites for useful info on VMware et al:

                http://www.yellow-bricks.com/

                http://blog.scottlowe.org/

                http://www.rtfm-ed.co.uk/

                http://www.run-virtual.com/

                http://www.vm-help.com/

                http://vsphere-land.com/

                Comment


                • #9
                  Re: VM Memory Confusion/Question

                  Originally posted by simondrake79 View Post
                  Ok, thanks for the links!

                  Also check out these sites for useful info on VMware et al:
                  Thanks Simon.

                  -Jason
                  MCSA/MCSE 2K3,MCITP:ESA,MCTS x 4,VCP x 2

                  Comment

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