>One of the main areas we are struggling with is understanding the effect of disparate systems sharing a large disk group on the EVA. Is there really a noticable performance penalty because of this or is it a wash against the benefits of using all of your spindles?
Depends on what you want to do. As a rule, disparate loads on the same physical discs is a recipe for pain. Having said that, a virtualised data centre presents a highly random load, so as long as you have enough physical discs to absorb the load, you should be OK. The trick is to size the array for the performance you need, not the disc space. If you get the performance right, the space usually takes care of itself. Both arrays work well, although I have to express my preference for HDS kit over HP
As far as management goes, all SANs are pretty simple to drive once you're used to the management console. The difficulty or ease of management is purely sales FUD. If you have multiple SANs, a product like Symantec's Storage Foundation and CommandCentral starts to make sense. Speaking of which, Symantec Storage Foundation path management software is free for servers with two processors or less and three attached LUNs or less. It may be worth your while evaluating Storage Foundation as an alternative to HP's or HDS' path management software.
Finally - don't be swayed by a free offer of HP Data Protector backup software - it sucks!
