It's been a few months since we announced some major changes to our virtualization support statements for Exchange 2010 (see Announcing Enhanced Hardware Virtualization Support for Exchange 2010). Over that time, I've received quite a few excellent questions about particular deployment scenarios and how the changes to our support statements might affect those deployments. Given the volume of questions, it seemed like an excellent time to post some additional information and clarification.
First of all, a bit of background. When we made the changes to our support statements, the primary thing we wanted to ensure was that our customers wouldn't get into a state where Exchange service availability might be reduced as a result of using a virtualized deployment. To put it another way, we wanted to make sure that the high level of availability that can be achieved with a physical deployment of the Exchange 2010 product would not in any way be reduced by deploying on a virtualization platform. Of course, we also wanted to ensure that the product remained functional and that we verified that the additional functionality provided by the virtualization stack would not provide an opportunity for loss of any Exchange data during normal operation.
Read more at source: http://blogs.technet.com/b/exchange/archive/2011/10/11/demystifying-exchange-2010-sp1-virtualization.aspx