In this video, Peter Schmatz, explained how Lync works in a virtualized server scenario. Lync supports virtualization, but there are some caveats that apply with Lync that don't necessarily with other servers. Peter talks about best practices for virtualizing Lync, and walked us through several of the virtualization scenarios that you might use when deploying Lync.
There's a great whitepaper "Server Virtualization in Microsoft Lync Server 2010" embedded below that goes in to lots of detail on planning and sizing Lync in a virtual environment:
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