This is great information - but there are VERY few tools that help you understand how many IOPs your system is actually using and if you are hitting that "wall". Vendor of the hardware always give you IOPs numbers and vendors of software almost NEVER do. Even high end enterprise arrays don't always provide a direct "iop-o-meter" especially when the lun is virtualized across many drives (and shared) this is helpful but not the holy grail of performance.