Microsoft’s latest whitepaper Best Practices for Virtualizing Exchange Server 2010 with Windows Server® 2008 R2 Hyper V™ contains good news for organizations that have hesitated to deploy Unified Messaging servers due to a lack of virtualization support.
Microsoft Exchange Server 2010 SP1 supports virtualization of the Unified Messaging role when it is installed on the 64-bit edition of Windows Server 2008 R2.
Unified Messaging must be the only Exchange role in the virtual machine. Other Exchange roles (Client Access, Edge Transport, Hub Transport, Mailbox) are not supported on the same virtual machine as Unified Messaging.
The virtualized machine configuration running Unified Messaging must have at least 4 CPU cores, and at least 16 GB of memory.
The Unified Messaging role was previously not supported for virtualization “due to the real-time response requirements associated with voice communications”.
This often seemed a weak reason because, as Steve Goodman points out:
Although it can be processor intensive, it’s not especially I/O intensive, nor does it require tons of storage and it can be scaled by the addition of further UM servers, load balanced by your PBX.
Note also that although Microsoft says “supports virtualization” it says so in a whitepaper about Hyper-V, so the support position for other virtualization platforms may be a different story.