Just a quick note – are you supported if you virtualise Exchange 2010 mailbox servers hosting Database Availability Groups ? The short answer is “yes”. The long answer is “Yes ….. unless you want to use Live Migration / XenMotion / VMotion … then you are NOT supported”.
To explain, DAG is a high availability strategy in and of itself. If you want to virtualise servers hosting DAG then you may but those servers should run on stand alone virtualisation hosts. Layering any sort of hardware higher availability on top of DAG high availability will invalidate your support. In truth, this shouldn’t be an issue as virtualisation only provides redundancy at the hardware level with Live Migration / XenMotion / VMotion whereas Exchange DAG provides hardware, O/S, binary and data redundancy (i.e. full redundancy) but you should take account of this in any plans you have for virtualising Exchange 2010.