Im looking for whitepaper to help me justify to management why Exchange runs better on mixture of virtualization (not Hyper-V/Vmware specific) and physical server CAS/HT: Virtual Mbx: Physical Mainly due to reason of the mailbox performance. Anyone care to share some of the whitepapers that can help me justify to management on the benefits?

I am not aware of anything neutral. All white papers I have seen have been sponsored by someone eager to show their solution is best. In my experience with Exchange, there is very little difference with running Exchange on bare metal compared to virtual machines. The only major difference is cost - as there is a little bit of additional overhead for the virtual machine platform. As long as the underlying hardware configuration is correct, the day to day operation and performance of Exchange isn't that different. From an operational point of view personally I prefer virtual machines, but I have clients that where it is on bare metal and that runs just as well. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

Like Simon wrote, there is a little overhead when running as virtual machine Make sure you check the performances before deploying, you can use jetstress and loadgen Also make sure you follow the support policies if you're going to deploy them as virtual machines http://technet.microsoft.com/en-us/library/cc794548%28EXCHG.80%29.aspxJonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

Agree with Simon and Jonas, it will be hard to find a neutral whitepaper from a vendor you can trust who supports your view that Exchagne runs best in a mixed virtual/physical environment. Given Virtualization's maturity these kind of arguments are in the past for most orgs and the focus is on making sure the specification and design is *right*, be it virtual or physical. The benefits of virtualisation can be tackled on their own and while most documentation fromt he Exchange team regarding Virtualisation is not focused on VMware or Hyper-V, it's more to do with what types of configurations are supported. It's never worth hiding behind a vendor's whitepaper for problems like this, as you'll be to blame if it's wrong anyway. It's better do your own research/testing using tools like Jonas mentions, or better still get a consultant with the experience you need to help you find what's right. SteveSteve Goodman Check out my Blog for more Exchange info or find me on Twitter