Oracle Real Application Clusters (RAC) is used to run critical databases with stringent performance requirements. A series of tests recently were run in the VMware performance lab to determine how an Oracle RAC database performs when running on vSphere 4.1
But Oracle has not certified any of its products on VMware virtualized environments. Oracle Support will assist customers running Oracle products on VMware in the following manner – Oracle will only provide support for issues that either are known to occur on the native OS or can be demonstrated not to be as a result of running on VMware