VMware vSphere provides comprehensive performance metrics for your needs on performance monitoring and diagnosis. These stats are available through not only vSphere Client but also vSphere APIs. To understand the overall performance management concepts, you want to read this article: Fundamentals of vSphere Performance Management.
Once having the basics, you may wonder what types of stats are exposed. The following table summaries all the 315 performance counters available in vSphere 4.1. As you might have guessed, the information is generated using open source Sphere Java API and then imported into WordPress using WP-Table Reloaded. You can easily sort and search the table.
My company has created products like vSearch ("Super vCenter"), vijavaNG APIs, EAM APIs, ICE tool. We also help clients with virtualization and cloud computing on customized development, training. Should you, or someone you know, need these products and services, please feel free to contact me: steve __AT__ doublecloud.org.
Me: Steve Jin, VMware vExpert who authored the VMware VI and vSphere SDK by Prentice Hall, and created the de factor open source vSphere Java API while working at VMware engineering. Companies like Cisco, EMC, NetApp, HP, Dell, VMware, are among the users of the API and other tools I developed for their products, internal IT orchestration, and test automation.