Two days ago VMware published a technical paper containing a comparative performance study of a large Oracle RAC instance installed on vSphere 5 and on a similar physical environment.
The results reveal that Oracle RAC, when virtualized with vSphere 5, performs within 7% of a corresponding physical environment. This information encouraged EMC IT to use vSphere to support their production Oracle RAC databases. This paper also provides best practices implemented while examining the performance of Oracle RAC on vSphere 5. Customers can use this information to optimize their own installations.