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  • Exchange 2003 Physical Memory Limit

    Hello,

    I have an exchange 2003 cluster (Active-Passive) with 4 gig of memory running on Windows 2003 Enterprise SP2.

    Every month, memory utilization comes close to 100%. I restart the Symantec email and file processes and this gets me back down until next month.

    I upgraded the passive node to 8gig hoping that although Exchange can only use 4 gig, the anti-virus and Windows could use the rest.

    I'm not sure but I think the link http://technet.microsoft.com/en-us/l.../aa997419.aspx says I'm wrong. It stats to yank out the memory or use the burnmemory boot.ini switch, but then goes on to say that a hotfix (which I already have installed) will allow other applications to use the extra memory without causing issues.

    My Exchange cluster is dedicated to exchange mailboxes but it has 2 different anti-virus apps, file and messaging, both from Symantec.

    Can having 8 gig on and Exchange server be beneficial in any way?

    Thanks

  • #2
    Re: Exchange 2003 Physical Memory Limit

    Exchange 2003 cannot use 8gb of RAM. I never put more than 2gb of RAM in to any Exchange 2003 servers. I have seen performance problems with more and remove the RAM (usually getting funny looks when I do) and the performance problems go away.

    Exchange will, by design, attempt to use all of the RAM on the system. That is normal. However it should give the RAM back when something else asks for it. 90% of RAM use is to be expected.
    However it is not unheard of for third party tools to cause problems - particularly those made by Symantec. They tie in to the store.exe process and cause the memory release behaviour to not work correctly.

    Simon.
    --
    Simon Butler
    Exchange MVP

    Blog: http://blog.sembee.co.uk/
    More Exchange Content: http://exchange.sembee.info/
    Exchange Resources List: http://exbpa.com/
    In the UK? Hire me: http://www.sembee.co.uk/

    Sembee is a registered trademark, used here with permission.

    Comment


    • #3
      Re: Exchange 2003 Physical Memory Limit

      Not what I wanted to hear but it validates what I've read. Thanks again Sembee.

      Comment


      • #4
        Re: Exchange 2003 Physical Memory Limit

        Are you using these switches?

        http://support.microsoft.com/kb/316739

        Comment


        • #5
          Re: Exchange 2003 Physical Memory Limit

          I suppose the question really is can Server 2003 use the extra RAM?
          The first link implies "if the machine is dedicated to running Exchange 2003". What's the definition of dedication here?

          This bit is interesting:
          Additionally, if you are running multiple applications that require the extra memory, you can run a Windows hotfix that will help prevent Exchange information store failures that could occur when there is more than 4 GB of RAM available.

          In this site we have 2 mailbox clusters both with 4GB ram each, /3GB and /USERVA:3030. Our PTEs aren't great (around 5000 to 6000) generally. Hardware DEP is enabled too. Store.exe usually sits around 1.2GB

          http://msexchangeteam.com/archive/20...05/407330.aspx
          cheers
          Andy

          Please read this before you post:


          Quis custodiet ipsos custodes?

          Comment


          • #6
            Re: Exchange 2003 Physical Memory Limit

            Howdy,

            I am using the switches /3GB /PAE /Userva=2970 in my boot.ini on the machine that has 4gig and I've tacked on the /burnmemory=4096 on the passive node that has 8 gig.

            My hope was that the definition of "dedicated" meant Exchange only and that the addition of Anti-virus software meant that it was no longer a "dedicated" Exchange server. Also, I had hopes that the "Additionally,..." paragraph meant that the Anti-virus would use the extra memory since I have the hotfix installed.

            I tend to believe that Sembee is right given his real world example but I still need to see it for myself. If I get approval, I'll fail over to the passive node and let it run for a couple of days to see what it does and I'll post the results.

            Thanks for the input guys.

            (http://technet.microsoft.com/en-us/l.../aa997419.aspx)

            Comment


            • #7
              Re: Exchange 2003 Physical Memory Limit

              Microsoft recommends setting /Userva=3030 for Exchange and only adjusting it for very specific reasons (to gain additional PTE's if they fall under a certain level). Can I ask why you've got it set to the lower threshold?

              http://support.microsoft.com/kb/810371

              Comment


              • #8
                Re: Exchange 2003 Physical Memory Limit

                Certainly I would go with his word myself. I have found 2970 is too low though, you should be able to adjust this and monitor the server though.
                If it is a HP server make sure the no execute disable bit is enabled in the bios/cpu/advanced settings.

                EDIT: Joe, stop posting whilst I am..
                cheers
                Andy

                Please read this before you post:


                Quis custodiet ipsos custodes?

                Comment


                • #9
                  Re: Exchange 2003 Physical Memory Limit

                  I did the /Userva=2970 when ExBPA gave me the "Free Page Table entries is at the critical threshold" message some time ago (
                  http://technet.microsoft.com/en-us/l.../aa996830.aspx). However, it may be worth resetting this back to 3030 and rerunning ExBPA.

                  The relevant line in my Boot.ini on the 4gig memory server is:
                  ..."Windows Server 2003, Enterprise" /fastdetect /redirect /NoExecute=OptOut /3GB /PAE /Userva=2970

                  Comment


                  • #10
                    Re: Exchange 2003 Physical Memory Limit

                    How much RAM does Windows see in total?
                    cheers
                    Andy

                    Please read this before you post:


                    Quis custodiet ipsos custodes?

                    Comment


                    • #11
                      Re: Exchange 2003 Physical Memory Limit

                      Unless the server is very busy I would think you would have sufficient PTE's with /Userva=3030 but I think your plan to set it back to 3030 and run the BPA again is the way to go. Since you'll have to reboot the server for the new setting to take affect I would wait a few days before running the BPA. I find that it takes a day or two for Exchange to "settle into it's groove".

                      OT: Andy: If you put on your tinfoil helmet I won't be able to read your thoughts anymore.

                      Comment


                      • #12
                        Re: Exchange 2003 Physical Memory Limit



                        Consider tinfoil hat attached!
                        cheers
                        Andy

                        Please read this before you post:


                        Quis custodiet ipsos custodes?

                        Comment


                        • #13
                          Re: Exchange 2003 Physical Memory Limit

                          Originally posted by AndyJG247 View Post
                          How much RAM does Windows see in total?
                          Task manager says 8,386,228K under the Perfomance Tab in the Physical Memory section.

                          Comment


                          • #14
                            Re: Exchange 2003 Physical Memory Limit

                            Well, I failed the cluster over to the machine with the 8gig of memory. The boot.ini has the switches:

                            /NoExecute=OptOut /3GB /PAE /Userva=2970 /BURNMEMORY=4096

                            I set Userva=3030 but go the same ExBPA error as before. It has been running for 2 days and has more physical memory available and is using less memory.

                            The /burnmemory=4096 is bringing the available memory down to ~4gig so i believe it's the /PAE that's giving me more. I'm not sure why the server is using less. I'll review to make sure the config and apps on both nodes are the same.

                            Clearly I've made too many changes at once to draw a conclusion, adding memory and adding the PAE switch. But I'm inclinded to believe that the PAE switched, not the memory upgrade gave me more memory.


                            Thanks to all for participating

                            Comment


                            • #15
                              Re: Exchange 2003 Physical Memory Limit

                              I'm a little confused at this point. Here's my understanding about the x86 memory architecture:

                              An x86 based 32 bit OS can only natively address 4GB of physical RAM (32 bit memory addressing).

                              The use of the /PAE switch in the boot.ini file allows the OS to use 36 bit memory addressing and therefore allows the OS to address physical memory above 4GB.

                              The /BURNMEMORY switch in the boot.ini file tells the OS no t to use a portion of physical memory.

                              So, why would you put more memory in and then tell Windows not to use it? I've re-read your post but am completely confused now as to what the exact issue is and what you're trying to accomplish. Could you recap it for us?

                              Thanks and sorry.

                              Comment

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