After installing vCenter (vSphere version 4.0) on my local PC to manage my VMware hosts, I noticed that my memory usage was extremely high, with the biggest culprit being Tomcat6.exe at almost a GB by itself even while the vCenter vSphere client was not running. Tomcat6.exe (Apache) is the web server vCenter uses and is listed in the services applet as VMware VirtualCenter Management Webservices. It is configured to start automatically by default and is also set to allocate a minimum of 256MB and a maximum of 1024MB of memory.
These values can be modified by either the Tomcat configuration utility (C:\Program Files\VMware\Infrastructure\tomcat\bin\tomcat6w.exe) or by editing the registry.
If using the configuration utility, you will want to click on the tab labeled “Java” and modify the “Initial memory pool” and “Maximum memory pool” values.
If you do not have the configuration utility installed, you can fire up Regedit and navigate to HKLM\Software\Apache Software Foundation\Procrun 2.0\vctomcat\Parameters\Java and modify the JvmMs (Initial) and JvmMx (Maximum) DWord values. I set both at 0, which will not reserve any memory that is not needed and will only use what it needs.