Lync is an instant communication application which provides many modalities to end users such as IM/Presence, A/V, Conferencing, Group/Persistent Chat, Enterprise Voice etc. To achieve all these functionalities, organizations need to deploy many roles on different-2 servers. Therefore, many roles require many servers and as number of servers will increase, cost will increase respectively. To provide better ROI with restraint TCO, Lync can be deployed as a Virtualized solution.

While virtualizing Lync, Performance and stability should be taken care. To achieve complete virtualized solution follow virtualization best practices for Lync.

Microsoft recommends below best practices for Lync virtualized solution.

Processor

• You should disable hyperthreading on all hosts.
• Do not use processor oversubscription; maintain a 1:1 ratio of virtual CPU to physical CPU.
• Make sure your host servers support nested page tables (NPT) and extended page tables (EPT). [Intel use EPT terminology while AMD use NPT terminology]
• Disable non-uniform memory access (NUMA) spanning on the hypervisor, as this can reduce guest performance.

Memory

• Do not configure dynamic memory or memory overcommitment on host servers.

Network

• Use Virtual Machine Queue (VMQ) to optimize synthetic NIC performance.
• Use physical NIC segregation for host versus guest communications.
• Single-root I/O virtualization (SR-IOV) is recommended. The specific configuration you should use depends on the host chipset and network adapter/driver. (SR-IOV is recommended but not mandatory, you can still use NIC teaming at host level.)

Storage

• Use fixed or pass-through disks rather than dynamic disks. (I recommend, use fixed disks in VHDX format instead of pass-through.)
• Use MPIO (Multipath I/O) for your storage Back End Server.

Hypervisor

• Virtual machine portability or failover techniques such as live migration are not supported.
• Hypervisors require an amount of overhead (typically 6 percent to 10 percent) above and beyond what the virtual guest requires. This overhead can involve both CPU and memory.
• Windows Server 2008 SP2 is not supported as a guest operating system.

Apart from Lync server roles, you can also virtualize other components such as Load Balancer and Session Broader Controller.