When you think of virtualization with Microsoft Lync Server 2013, several things might come to mind. For starters, basic workloads can be virtualized, such as IM\presence, conferencing, and application sharing. One workload that was definitely a no-no for Lync virtualization previously was any role that involved voice. Lync Server 2013 brings many new and exciting features, including being able to use virtualization with all server roles, including voice. Today's focus is on how to best set up a virtual Lync environment, paying particular attention to hardware and networking considerations as well as supported configurations.

Hardware and Networking Considerations

Two key considerations for running Lync Server 2013 in a virtual environment are the host operating system and the virtual operating systems. You can run either Windows Server 2012 or Windows Server 2008 R2 for both host and virtual OSs. Lync Server 2013 supports running the host and virtual operating systems in a mix configuration. For example, customers can have a host server running Windows Server 2012 and have virtual servers running on that host running Windows Server 2008 R2, or vice versa. In addition, Lync Server 2013 is supported on both Hyper-V and VMware technologies.

The following specifications show the basic hardware requirements for virtualization:

  • Server -- an enterprise-grade server that includes a minimum of two CPU sockets
  • CPU -- any CPU that can support at least 24 virtual cores
  • Network adapter -- two or more 1 Gigabit Ethernet (GbE) or 10 GbE adapters
  • Memory -- at least 32GB; each host should have 4GB for the host plus additional memory for each server role it hosts

Keep in mind your network performance as well because Lync Server is a real-time communications application that relies on optimal networking conditions. Performance plays a pivotal role especially when we bring voice into the picture. A Lync Server workload that contains media can reach peak network utilization of up to 500Mbps. How do network conditions and servers relate to each other?

The physical server that hosts the virtual machines (VMs) running Lync Server roles must have at least one network adapter dedicated to the virtual Lync roles. If one host server will run multiple virtual servers that are each responsible for media workloads, make sure the network adapter that's used can handle the traffic. If it can't, users could notice disparity in the voice quality of calls through Lync.

With Lync Server 2013, out of the box you can gather statistics about IM, conferencing, application sharing, and Enterprise Voice. With the Monitoring role now being collocated on the Lync Front End Server, there's no need to find extra hardware to leverage the Monitoring server capabilities. Many of the voice- and media-related out-of-the-box reports display statistics for the call quality, which lets administrators take appropriate actions for finding remedies to end users experience, which could be anything from swapping out users' headphones to modifying the network adapters' throughput speed.

Supported Topologies

Something to consider going forward is that you can't mix and match virtual and physical servers in the same Lync pool. What this restriction means is that you can't have some Front End servers running virtual and others physical in the same pool. Now, the back-end Microsoft SQL Server database in this scenario is considered separate. So you can have virtual Front End servers and a physical back-end SQL Server instance and be in a supported configuration. Or you can have physical Front End servers and a virtual back-end SQL Server.

Lync Server supports virtualization for the following roles or servers:

  • Lync Enterprise Edition servers -- multiple servers that each support key workloads for Lync, pooled together to provide resiliency
  • Back End SQL Server -- a back-end server for Lync databases
  • Lync Standard Edition servers -- a single Lync server that handles all workloads * Monitoring server -- allows Lync to gather call detail records
  • Director server -- provides security for an organization by filtering traffic through a single point of reference
  • Persistent Chat server  -- lets users participate in persistent work IM sessions
  • Edge Server -- responsible for allowing remote users to participate in IM, conferencing, and Enterprise Voice

Keep in mind that a running SQL Server Back End is reliant on presence for users, so if you do have a virtual back-end, make sure you're not running additional applications on the host.

Final Thoughts

It's about time that Microsoft supports an entire Lync deployment in the virtual space. With Lync Server 2010, virtualization was supported but there were many caveats that we won't go into because that would take another entire article. As far as media goes, not needing physical servers for audio\video conferencing, Edge Servers, and Mediation Servers can save customers money on hardware. At the end of the day, it looks like going virtual for Lync Server 2013, whether you're running Hyper-V or VMware, could be a move in the right direction, specially because a lot of organizations are already heading in that direction to save space and money. (For additional information about how to get Lync implemented in your company, see Nathan Winters' "Business Benefits of Unified Communications.")