With the release of SP2 for Exchange 2003 we have published the support policy for Exchange Server 2003 running on hardware virtualization software KB article:
Exchange 2003 SP2 on MSVS 2005 R2 Test Summary
The support policy described in the article above is a result of a team effort conducted by the Exchange CXP Solutions, MSIT, the VS product group, and Exchange SP2 Test teams:
Support policy for Exchange Server 2003
Microsoft supports Exchange Server 2003 running on hardware virtualization software (virtual machines) only when all the following conditions are true:
Frequently Asked Questions
Q: Do we support Exchange Server 2003 SP1 or below on Virtual Server?
A: No, Virtual Server testing was introduced only on SP2, so that is the minimum version we support.
Q: Do we support Exchange Server 2003 SP2 on Virtual Server 2005 RTM?
A: No, Microsoft Virtual Server 2003 R2 is the version that the Exchange 2003 SP2 tests and production testing ran on so it is the minimum required version.
Q: When Microsoft Virtual Server R2 is going to be available?
A: It is expected to be available in November/2005.
Q: Do we support Exchange on other virtualization platforms?
A: Microsoft has a general support policy for running Microsoft software in non-Microsoft hardware virtualization software. The policy also applies to any version of Exchange Server that is running in non-Microsoft hardware virtualization software. The link is on the KB article.
Q: Why is Exchange clustering not supported?
A: Because it was not a tested scenario for this version of Virtual Server.
Q: How do we determine the scalability limitations of Exchange 2003 SP2 when running on Virtual Server?
A: Use the Exchange load simulation tools in the same way you would for a physical machine.
Q: I ran Loadsim and Jetstress simulating the expected user profile and number/size of mailboxes and the performance looks good. What else should I worry about?
A: You need to determine how long it is going to take to backup Exchange over the network and validate that against the SLA for backup time, in order to determine the number of mailboxes that will reside on that server. Also, you need to ensure that you consider the load of all virtual machines on the same host. The overall host performance will impact the virtual server performance.
Q: If I run Exchange on a virtual machine, can I just backup the VHD files?
A: No, Exchange backups are still required in order to provide a proper data recovery and transaction logs commit.
Q: Where can I find best practices for configuring Virtual Server?
A: See the MS Virtual Server administrator’s guide. The link is on the KB article.