Recently, I needed to capture some performance data from the host of a virtualized SQL Server. There is a utility called "esxtop" that if run from the ESX Host Command Line, it displays text-based information in columns similar to that which you see in Windows Task Manager. That is handy, but I wanted to get this to a file.
If you run the following command "esxtop -a -b >results.csv" at the same prompt, all VMWare Performance Counters are sent to this file until Ctrl-C is typed in at the Command Prompt. This CSV file may be opened by Excel and even Perfmon in Windows! There are a lot of counters to look at. Some make a lot of sense; others don't. The description for many of these counters may be found online by searching for the counter name.
For the environment that I was investigating, I was able to determine from some of these counters a few things that were masked by the Virtual Environment. This provided additional insight. As VMWare and SQL Server become more common bedfellows, it is important to know how to monitor the systems.