VMware has released another great “technical paper” regarding Performance Best Practices for VMware vSphere 4.1. It can be found in the Technical Resource Center which by the way contains a lot of awesome docs.
The technical paper, Performance Best Practices for VMware vSphere 4.1, provides performance tips that cover the most performance-critical areas of VMware vSphere 4.1. It is not intended as a comprehensive guide for planning and configuring your deployments.
Chapter 1 - “Hardware for Use with VMware vSphere,” provides guidance on selecting hardware for use with vSphere.
Chapter 2 - “ESX and Virtual Machines,” provides guidance regarding VMware ESX™ software and the virtual machines that run in it.
Chapter 3 - “Guest Operating Systems,” provides guidance regarding the guest operating systems running in vSphere virtual machines.
Chapter 4 - “Virtual Infrastructure Management,” provides guidance regarding resource management best practices.
http://www.vmware.com/pdf/Perf_Best_Practices_vSphere4.1.pdf