Tomcat for vCenter – Memory Tuning

The memory requirements for the Tomcat service (aka VMware VirtualCenter Management Webservices service) has doubled from vCenter 2.5U5 and vCenter 4.0U1.  Going from 128MB to 256MB as the minimum (JvmMs). At the same time the maximum memory setting is 4x higher, from 256MB to 1024MB (JvmMx).

If you have access to both environments, you can check by yourself. Open up REGEDIT and navigate to HKLM\SOFTWARE\Apache Software Foundation\Procrun 2.0\WebAccess\Parameters\Java
Compare the DWORD values for JvmMs and JvmMx for both installation. To learn more about those settings, visit the web site.

Now the fact that vCenter 4.0U1  uses Tomcat6 doesn’t explain this big appetite and in my nested environment where memory is a rare element I didn’t want to have a process taking too much memory resources.

Thus I edited the registry keys and set them to 0 (zero), then restart VMware VirtualCenter Management Webservices service and in Task Manager, checked the memory usage for tomcat6.exe.

Columns are Mem Usage, Peak Mem Usage and VM Size. For Windows 2008 and Vista/W7 the columns are Working Set, Peak Working Set and Memory (Private Working Set) and Commit Size.  

JvmMx defines the VM Size/Commit Size. It allocates x mega bytes of memory whether the process will use it or not. By setting the registry key to 0 (zero) the VM Size/Commit Size will grow along with the process loading up, using exactly what is necessary, that is 256MB in my environment thus saving me roughly 756MB.

For more information about the columns in Task Manager, read this KB at Microsoft.


About PiroNet

Didier Pironet is an independent blogger and freelancer with +15 years of IT industry experience. Didier is also a former VMware inc. employee where he specialised in Datacenter and Cloud Infrastructure products as well as Infrastructure, Operations and IT Business Management products. Didier is passionate about technologies and he is found to be a creative and a visionary thinker, expressing with passion and excitement, hopefully inspiring and enrolling people to innovation and change.
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10 Responses to Tomcat for vCenter – Memory Tuning

  1. Pingback: VMware vCenter Webservices service chewing up all your memory? «

  2. InfoWiz says:

    After changing the ram settings on our vmware vcenter 4U1, we get
    Unable to connect to web services to execute query
    When doing searches in the vsphere client. Also the “hardware status” tab also bring up an error. Reverted back to the old config.

  3. Pingback: VMware vCenter memory usage issues – tomcat6 « adventures {in}security

  4. deinoscloud says:

    Jason Boche just published an excellent article (as usual) about Tomcat+vCenter and memory mgmt. I urge you to read his post at

  5. Mike Murphy says:

    For what it’s worth, I have vCenter 4.1, and Tomcat was using 2GB of RAM when collecting datastore performance data. Reports would fail to load, so we increased the max ram setting in Start > Programs > Tomcat > Configure Tomcat to 4GB. Now, Tomcat is consuming 3.6GB when running the reports, and the reports load. Granted, I think it’s too bad that this process is so heavy on RAM & CPU (90%), but it’s what VMware support tech told me was the issue. I actually found an error in the logs saying “out of memory.”

  6. deinoscloud says:

    Hi Mike,

    3.6GB amazingly that looks like the maximum addressable memory of a 32bit OS… Are you running vCenter 4.1 on a 32 bit system???

    Anyway you’re right that Tomcat is an hungry process and if you’re running in prod, do not hesistate to give it what it requests 😉

    Thx for your comment BTW!


  7. Nick says:


    FYI: vCenter 4.1 cannot be run on a 32-bit machine

  8. Pingback: A Year Blogging In Summary And Season’s Greetings « DeinosCloud

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