This was reposted from SQL Server http://channel9.msdn.com/Events/TechEd/NorthAmerica/2012/DBI317 written by (author unknown). They get all the credit for this, not me.
In this session, learn what you should be looking at within your virtual environment to ensure you are getting the performance you should out of it. This includes how to look for CPU performance issues at the host level. We also discuss the Memory Balloon drivers and what they actually do, how you should be configuring them, and why. We discuss some of the memory sharing technologies which are built into vSphere and Hyper-V and how they relate to SQL Server. We finish up with some storage configuration options to look at. #TEDBI317
Additional reading can be found at the original author’s post.