Following these two best practices documents might not be enough. Please take a look at following performance study:
SAP batch workload performance on Linux - vSphere - UCS
Although this has been done on Linux and on Oracle as a database, the effects can be similar with other OS and DB.
I strongly recommend that you work through these two documents thoroughly:
Best Practices for Performance Tuning of Latency-Sensitive Workloads in vSphere VMs
Performance Best Practices for VMware vSphere 5.1
Or if you have vSphere 5.5:
Deploying Extremely Latency-Sensitive Applications in VMware vSphere 5.5
Matt