This is where the current vendor approach to VMs lacks a holistic view and how Forsythe is approaching this market differently. The virtual machine software manufacturers have done a great job integrating VM management software as well as migrating the physical servers to be able to utilize networked storage and integrate with storage management. But they typically only measure the server aspects of performance (CPU, memory and maybe network I/O) and how much software you need (i.e., how much consolidation can you do and how many licenses do you need.)
We insist on reviewing the storage performance characteristics, which are readily available via the the data collection tool as a part of a capacity planning or virtualization assessment. The metrics are available: You simply need to check the box that collects them for you to view. If you can split out the I/O characteristics related to storage by device and by application, you will have a good head start.
Forsythe Solutions Group