The input/output operations per second (IOPS) metric is a key way to measure just how much data can be exchanged from the storage and the virtualization arenas. Knowing how many IOPs our VMs drive, our hosts drive, and our storage can handle is critical when you are troubleshooting issues and trying to map out your future capacity needs.
Without an expensive monitoring tool or the experience to run and interpretesxtop, then the administrator will have a challenge of trying to gather the IOPS information some other way.
This script, from Curtis Salinas, inspects the performance of VMs in your vSphere environment and analyzes hosts and VMs throughout the data center. The script can display the results to the screen and a .CSV file and can help track down which VMs are eating up more than their share of resources and straining your storage system.