If you’re used to working with VMware, you probably know about the nifty little utility esxtop. This tool allows you to view real-time performance data on a ESX host. It also allows you to gather performance metrics in batch mode, which allows you to analyze the data in eg. Excel or ESXplot.
For those who are working with XenServer, a similar utility is available called xentop. The xentop utility allows you to monitor real-time performance metrics, like esxtop does. However, gathering data like in esxtop is a challenge.