I came across another nice tool in ESX 3.02 that gives a quick view of the resources in use – and the virtual machines position within the usage. If you have used much Unix or Linux, you have probably come across the top package. While top is not a very fancy package, it is available in ESX – and it does not really provide much useful information. ESX, however, provides a utility called esxtop that shows summary information on resources and the virtual machine inventory on the host. Take the following image example:
This gives a nice view of the resources being used by the ESX host – in VMware’s talk. One nice feature is that esxtop gives a nice safeguard in that the refresh interval minimum is two seconds. Old school top could have a refresh interval of 0 seconds by typing “s” to specify seconds, and entering zero. Then top would be the highest offender and quickly chew up resources. Interpreting this screen takes some pre-reading. For example, at the top of the screen, there is a value for CPU load average. The value of .25 indicates that this system averages only 25% utilization. If I were to see this system with a value of 1 – it would be fully utilized on average. Dig into the ESX Resource Management Guide online for some more options and configuration variables. Exiting esxtop is simple enough by entering “q” to return to the x shell.