What does the following command return as output?
vdf -h
Can you initiate a "/etc/init.d/sfcb-watchdog stop" after a reboot of the server and see if the issue still occurs.
Some explanation on the sfcb service: This is the service providing you with the hardware status tab in vCenter or in on the configuration page when connected directly on the host. It is an extendible system which means third party providers can use the base CIM system to add sensors to watch.
From time to time such a CIM provider can actually have a memory leak (not only 3rd party proivder's are at fault here, also the basic ones installed in the vanilla image can cause this).
Do you have any dumps in /var/core ?