Whenever I have setup a new VMware system I normally run a few rounds of iometer in order to measure the performance of the system. By doing this I can verify if the system is performing as expected, and if it's not I can tune the system until it does. If it's a new type of system I can see if there are others with a similar system who have posted their results to the VMTN that I can compare my results with.
As long as a system has enough memory, disk performance is the most common bottle neck. If we after having the system up and running in production for a while run into performance issues, we can in the process of narrowing down the bottle neck compare our new iometer results with the old ones that were captured when the system was new.
The video above uses a 5MB test file. On a few newer storage arrays you may need to use a larger test file in order to get useful results.
If you haven't read through the VMTN threads before, please have a look to find some examples of people who have uncovered issues with their systems and fixed them. As quite a few people didn't fully understand how to get the right numbers of the resulting csv file I put up a little web page that will take care of that. It should now be so easy that even your mother could do it :)
Open unofficial storage performance thread
New open unofficial storage performance thread