We have an issue with one of our vCenter servers using
VMware vCenter Server 5.0.0.16964
This server is running on Windows Server 2008 R2 in a virtual machine with 4 vCPUs and 8 GB of memory.
It appears that the main vCenter executable, vpxd.exe can often use up physical memory to the point where Windows task manager reports 99% of memory is consumed. Typically, this is around 6.5 GB of memory consumed by vpxd.exe. At this point, existing vSphere client connections to vCenter are terminated and no new connections can be established.
The only way found to resolve this problem is to "End Task" on the vpxd.exe process and start the vCenter service again. The vCenter service will not respond to a stop service request.
Also running on this vCenter server is:
VMware SRM 5 service with vSphere replication enabled
vSphere Update Manager
VirtualCenter Management Webservices