Global Solutions Engineering completed a study of Microsoft Lync Server 2010 in a virtualized environment on the new Dell PowerEdge R720. Microsoft Lync Server provides enterprise-grade communications for instant messaging, web/audio/video conferencing, application sharing, and telephony (or VOIP). In A Sizing Study of Microsoft Lync Server 2010 on a Virtualized Dell PowerEdge R720, Global Solutions Engineering presents a reference configuration - reproduced below - as well as performance results.

Reference Configuration

With the 12th generation of Dell servers, new memory, processor, and NIC options allow for better consolidation of virtualized Lync Server Roles. As can be seen above in the Reference Configuration, there are many roles in Lync Server, and all can be virtualized based on the Lync in a Virtualized Environment Whitepaper's guidance. Since the Front End Server role provides application-level high-availability and needs many instances, it is a strong candidate to benefit from Hyper-V virtualization. Based on Microsoft's Virtualized Environment Configurations and Dell's Virtualized Environment best practices, we configured the PowerEdge R720 in th following configuration:

R720 Configuration

Server Dell PowerEdge R720
CPU Two Intel Xeon E5-2660 with 8 cores at 2.20 GHz
Memory 96 GB
Operating System Windows Server 2008 R2 with Service Pack 1
VM Configuration Four vCPUs and 16 GB Memory

The R720 provides the latest Intel processor and support of 96 GB of memory with a maximum supported 768 GB of memory, pushing the limits of virtualization performance for the front end Server Role VMs. With this CPU and memory increase, one R720 can support four Lync Front End VMs with 4 vCPUs and the recommended 16 GB of Memory with a 1:1 ratio of physical to virtual CPUs. It is important to boot the front end VMs from a Storage Area Network such as the Dell EqualLogic PS6100. SAN Booting is network intensive and proper segregation of SAN and LAN on separate network ports(NICs) and switches should be maintaine. To prevent any bottlenecks across 4 Front End VMs, we used 4 1 Gb NICs for SAN with Multipathing IO through EqualLogic's Host Integration Tool turned on and 4 NICs teamed with the Broadcom Advanced Control Suite 4. With plenty of physical memory, the Lync Front End VM's performance will scale linearly and not cause any bottlenecks. For more detailed information about Lync Server Roles and their solutions, be sure to check out the Lync Reference Architecture and for more detailed performance results, download the Sizing Study.