We recently ran the Dell Performance Analysis Collection kit which monitors your servers via WMI for 24 hours. You send the file off to Dell and they return a report with graphs of IOPS and MB/S disk usage.
This uncovered some interesting stats for us which we'd like to look further into. This is just a sales tool for Dell, but is there a similar tool that we can download/purchase for use that generates our own reports? Even better would be ot tell us what processes are using the IO.