5 Replies Latest reply on Mar 12, 2009 11:57 AM by IdeCable

    Server 2003 VM & users getting kicked out of MS Access files

    nmpdan Lurker

      Hi all.

       

      A billing app built on top of MS Access 2003 and Crystal Reports is run via remote desktop on the Windows server VM.  There are times when this billing app is run that all users are kicked out of their MS Access files that are being accessed via the Windows share and they can not re-open them until the billing app is stopped or in extreme cases the linux host server is rebooted.  I have attached the log file entries for the VM for the day of latest occurrence.  Currently, this is the only VM on the host box.  vmstat is not showing anything crazy by the time I'm contacted to check it out and nothing is showing up in /varlog/messages.  The latest occurrence was Feb. 16, 2009 and I've attached the VM's vmware.log file and hosts hostd.log file showing entries during the relevant time.  I'm seeing

       

      vmx| scsi0:0: Command WRITE(10) took XXXX seconds (ok)

      vmx| scsi0:0: Command READ(10) took XXXX seconds (ok)

       

      and occasional

       

      vmx| DISKLIB-LIB   : numIOs = 7550000 numMergedIOs = 0 numSplitIOs = 0

       

      entries in the VMs log

       

      Can anyone give any insight?

       

      Thanks.

       

      ~Dan

       

      SPECS:

       

      Host: Centos 5.2 32bit

      Dual-core AMD Opteron

      4GB ram

      2.6.18-92.1.22.el5PAE

      1TB SATA software RAID1

      ext3 FS

      Server 2 build  122956

       

      Guest: Windows 2003 Standard SP2

      C: 40GB split files

      D: 500GB split files

      Memory: 3GB

      CPUs: 2

        • 1. Re: Server 2003 VM & users getting kicked out of MS Access files
          fixitchris Expert

           

          Has this billing app + RDP access been in production on a physical server prior to virtualization?

           

           

          Is the VM OS still accessible when the app crashes?

           

           

          Why do you think it's the VM?

           

           

          Is it possible that windows RDP is causing this problem?  I've seen similar problems happen with apps run over RDP before.

           

           

          • 2. Re: Server 2003 VM & users getting kicked out of MS Access files
            nmpdan Lurker

            Yes, the app was run on an OLD physical server prior to the VM w/o problems, although, I'll have to verify if they used RDP or not.  I'll have them try a different remote desktop solution and see how that works.

             

            The VM most of the time is still accessible.  Occasionally, it becomes unresponsive and the VM is rebooted via the console.

             

            I'm leaning more toward it possibly being the host rather than VM itself, although, this app is god aweful and the multiple mdb files have to regularly compacted to avoid the Access 2GB limit.  They currently have a developer redoing the whole thing using MSSQL and will dump Access, but that is months away at the earliest.

             

            Thanks.

            • 3. Re: Server 2003 VM & users getting kicked out of MS Access files
              fixitchris Expert

               

              Can you post the VMX file for the guest?

               

               

              You're right, Access can get pretty aweful.  So the databases and the app are local to the guest OS?  Can you also turn on a couple of performance counters on the guest for a period of time (cpu utilization/ page file swapping/ memory... )?

               

               

               

               

               

              • 4. Re: Server 2003 VM & users getting kicked out of MS Access files
                nmpdan Lurker

                I'm going to setup some counter tomorrow and see what I get.  They used to use LogMeIn on the old server, so I'm having them switch to that as well.  I'll pop back in a couple days with more information.

                • 5. Re: Server 2003 VM & users getting kicked out of MS Access files
                  IdeCable Novice

                  You cannot expect to get everthing working in one slap - without having to tweak the host OS for VMWare. You need to tweak your VMWare. I had the same errors you had by the way.

                   

                  Ok here we go:

                   

                   

                   

                  By the way I use Ubuntu 8.10, but these tweaks could be valid for other Debian based systems.

                   

                   

                   

                  You will have to create a ramdrive from fstab add the following in /etc/fstab

                   

                   

                   

                  tmpfs    /tmp/vmware    tmpfs    defaults,size=100% 0 0

                   

                   

                   

                  and from a root shell create /tmp/vmware directory

                   

                   

                   

                  mkdir /tmp/vmware

                   

                   

                   

                  Next: open and edit /etc/vmware/config

                   

                   

                   

                  add the following entry:

                   

                   

                   

                  tmpDirectory = "/tmp/vmware"

                   

                   

                   

                  mainMem.useNamedFile = "FALSE"

                   

                   

                   

                  sched.mem.pshare.enable= "FALSE"

                   

                   

                   

                  MemTrimRate = 0

                   

                   

                   

                  MemAllowAutoScaleDown = "FALSE"

                   

                   

                   

                  prefvmx.useRecommendedLockedMemSize = "TRUE"

                   

                   

                   

                  prefvmx.minVmMemPct = "100"

                   

                   

                   

                  And lets restart your virtual machines, with the proper ramdrive installed:

                   

                   

                   

                  mount /tmp/vmware

                   

                   

                   

                   

                   

                   

                  /etc/init.d/vmware stop

                   

                   

                   

                  /etc/init.d/vmware start

                   

                   

                   

                  In details:

                   

                   

                   

                  We told VMWare Server to only use the .vmem files to the temp directory VMWare uses. That was done using mainMem.useNamedFile = "FALSE"

                   

                   

                   

                  And to also told VMWare Server to specify the path to the temp directory, and that was done using  tmpDirectory = "/tmp/vmware"

                   

                   

                   

                  I saw imdiate improvements when I did this.

                   

                   

                   

                  The rest of the config tweaks I mentionned was only to tell VMWare Server to lock the allocated memory for the VM to make it stay in the RAM. That's a good performance tweak.

                   

                   

                   

                  There are other things worth doing if you are under a Debian based system:

                   

                   

                   

                  in /etc/sysctl.conf

                   

                   

                   

                  vm.dirty_background_ratio = 5

                   

                   

                   

                  vm.dirty_ratio = 100

                   

                   

                   

                  net.core.wmem_max = 16777216

                   

                   

                   

                  net.core.rmem_max = 16777216

                   

                   

                   

                  net.ipv4.tcp_timestamps = 0

                   

                   

                   

                  net.ipv4.tcp_rmem = 4096 262144 16777216

                   

                   

                   

                  net.ipv4.tcp_wmem = 4096 262144 16777216

                   

                   

                   

                  net.core.optmem_max = 524288

                   

                   

                   

                  net.core.netdev_max_backlog = 200000

                   

                   

                   

                   

                   

                   

                   

                   

                   

                  These are extra settings that I founded on the net, that have not done harm yet.  Worth giving a shot too.

                   

                   

                   

                   

                   

                   

                   

                   

                   

                  When reading vmware.log files, always read between the lines.

                   

                   

                   

                   

                   

                   

                   

                   

                   

                  I will provide additional details onto extra config tweaks I am about to text this weekend, I'll keep u posted.

                   

                   

                   

                   

                   

                   

                   

                   

                   

                  PS: the solution I explained works for my system, I only use one VM in this box..

                   

                   

                  Marc