Initially with Exchange 2010, Microsoft did not support virtualization of the Unified Messaging role. With the release of Exchange 2010 SP1, Microsoft has changed their support stance and has announced full support for the virtualization of the Unified Messaging role. This is totally consistent with the virtualization stance for Microsoft Unified Communications products.
You can see the virtualization announcement for Exchange 2010 Unified Messaging here:
How does this affect Exchange 2010 capacity?
- Exchange 2010 UM servers should have 4 CPU cores and 16 GB of RAM
- Testing showed that virtualized UM servers of this configuration support 40 concurrent calls with voicemail preview enabled
- Testing showed that virtualized UM servers of this configuration support 65 concurrent calls without voicemail preview enabled
- Average concurrency ratio of active mailboxes to active voicemails is 100 to 1.
- Expected capacity of virtualized Exchange 2010 UM servers is 4,000 to 6,500 users respectively
The following guide walks through Exchange 2010 Unified Messaging planning within virtualization, as well as other virtualization requirements:
Core System Requirements:
We’ve found in pre-announcement testing that the virtualization of the Exchange 2010 Unified Messaging role works as expected. We have not experienced negative performance or quality effects of virtualization of the Unified Messaging role, assuming capacity requirements are taken into account.
Also note that Lync 2010 is fully supported virtualized:
See the following for Lync 2010 virtualization capacity planning information: