Aitor - Thanks for the lengthy explanation. This is exactly the kind of stuff I am looking for. I am going to read over everything a bit more and may have some follow-up questions, but I wanted to go ahead and clarify that I will be running two of these SANS for HA - so my budget is already doubled....

I am looking to build a large HA storage pool (anywhere from 10-40TB) which will be used as primary storage for around 200 XEN server instances. The XEN instances are for use by our clients and as such, there functions will vary. We foresee that around 80% of the instances will be Windows based and ...