Running in a Virtualized Environment
Topic Last Modified: 2012-10-17
Microsoft Lync Server 2010 supports virtualization topologies that support all Lync Server 2010 workloads—instant messaging (IM) and presence, conferencing, Enterprise Voice, Monitoring Server, and Archiving Server. Windows Server 2008 R2 is required. Lync Server virtualization supports Hyper-V and equivalent virtualization platforms. This section briefly discusses the virtualization support. For details, see https://go.microsoft.com/fwlink/p/?LinkId=211394.
Supported Topologies
You can mix physical and virtual servers in your deployment, with only the following restrictions:
You cannot mix different types of servers within the same pool. All servers within the same pool must either be physical or virtual. For these purposes, Front End Servers and SQL Servers running the back-end database are considered to be separate, meaning that you can have virtual Front End Servers using a physical back-end database, or physical Front End Servers and a virtual back-end database. Note however that the back-end database has a real-time requirement for presence updates, which is unlike many SQL Server applications. If you run a virtual back-end database you must be aware of performance issues, especially if the host of the virtual back-end database is running other applications.
This is the only limitation to mixing physical and virtual servers. You could have one Front End pool of physical servers and another of virtual servers. And you can deploy different pools and servers as either physical or virtual in any combination.
All servers within one pool should provide about the same performance. For example, if you have virtual Front End Servers in one pool being hosted on different host servers, you should make sure each virtual Front End Server is capable of a similar level of performance.
If you are deploying a large amount of virtualized servers across different host servers, you should consider spreading out the members of one pool across different host servers. For example, in a pool of eight virtual Front End Servers, deploy four on one physical host and four on another. While this is not a true high-availability solution, it does provide some protection if a single host server fails.
Recommended Host Server Configurations
The following table shows the recommended base hardware for a host server.
| Component | Recommendation |
|---|---|
Server |
Enterprise-grade server, with a minimum of two CPU sockets |
CPU |
Intel Xeon 5500 series or AMD Opteron 6100 series, 2 Gigahertz or greater, recommended for best performance. Support of nested page tables (NPT) or extended page tables (EPT) is recommended. |
Network adapter |
Two or more 1GbE or 10 GbE adapters. Virtual Machine Queue (VMQ) is recommended. |
Storage |
Two or more serial advanced technology attachment (SATA) or serial attached SCSI (SAS) hard disk drive, 10k rpm or higher direct attach storage (DAS), or equivalent storage. RAID 1 or equivalent SSD. |
Memory |
At least 32 GB. PC2-6400 double data rate (DDR2) or PC3-8500 DDR3 is recommended. |
Both the physical host servers and all virtual servers must run Windows Server 2008 R2 with the software update described in Microsoft Knowledge Base article 981836, "Network connectivity for a Windows Server 2003-based Hyper-V virtual machine is lost temporarily in Windows Server 2008 R2," at https://go.microsoft.com/fwlink/p/?LinkId=3052&kbid=981836.
Note
You must run this update on both the physical host server and all virtual machines, even though the Microsoft Knowledge Base article states otherwise.
Networking Considerations
Lync Server provides real-time communications, and depends on fast and efficient networking. If a packet is delayed by as little as a few milliseconds, users might detect an audio glitch, experience a delayed call, or frozen video. To improve the network performance of your virtualized topology, you should do the following:
The host must have at least one network adapter dedicated to the virtual machines running Lync Server roles. Sharing a network adapter with the host or with a storage area network (SAN) is not recommended.
Note that a Lync Server workload that includes media (Front End Servers and A/V Conferencing Servers) can reach a peak network utilization of more than 500 Mbps.
If one host server is running multiple guest virtual servers that each run Lync Server media workloads, ensure that the host network adapter can handle the traffic. To prevent bottlenecks, consider a higher speed network adapter (such as 10 GbE) or multiple network adapters using link aggregation.
Enable virtual LAN (VLAN) tagging on the network adapter, and implement multiple VLANs on the virtual servers to optimize network traffic.
Implement multi-path I/O (MPIO) to your back-end database.
Use network adapters enabled for Virtual Machine Queue (VMQ). VMQ is a virtualization technology for the efficient transfer of network traffic to a virtualized operating system. VMQ allows the VMs to filter the queue of packets within the network adapter, resulting in improved efficiency of network traffic. If you use these network adapters, you can enable VMQ for each virtual machine using the hypervisor’s management console.
Virtual Server Scaling
To provision enough virtual servers for your needs, use the following table to compare recommended scalability of physical and virtual specifications for Lync Server 2010 roles.
| Server role | Physical | Virtual | ||||
|---|---|---|---|---|---|---|
CPU |
Memory |
Number of users supported |
CPU |
Memory |
Number of users supported |
|
Front End Server, all workloads |
8 cores |
16 GB |
10,000 |
4 cores |
16 GB |
5,000 |
Front End Server, IM and presence only |
8 cores |
16 GB |
25,000 |
4 cores |
16 GB |
12,500 |
Standard Edition server, all workloads |
8 cores |
16 GB |
5,000 |
4 cores |
16 GB |
2,000 |
Standard Edition server, IM and presence only |
8 cores |
16 GB |
10,000 |
4 cores |
16 GB |
10,000 |
Director |
4 cores |
4 GB |
20,000 concurrent users |
2 cores |
3 GB |
8,000 concurrent users |
Monitoring Server and/or Archiving Server |
8 cores |
16 GB |
100,000 or more |
4 cores |
8 GB |
100,000 |
A/V Conferencing Server |
8 cores |
16 GB |
20,000 |
4 cores |
12 GB |
10,000 |
Mediation Server (stand-alone server) |
8 cores |
16 GB |
800 concurrent calls |
4 cores |
10 GB |
400 concurrent calls |
Edge Server |
8 cores |
16 GB |
15,000 users concurrently connected through the Access Edge Service |
4 cores |
8 GB |
7,500 users concurrently connected through the Access Edge Service |
Survivable branch server |
2 cores |
2 GB |
1,000 |
2 cores |
2 GB |
1,000 |
Back-end database |
8 cores |
32 GB |
80,000 |
4 cores |
16 GB |
40,000 |
Monitoring and Archiving Database |
8 cores |
16 GB |
230,000 |
4 cores |
12 GB |
115,000 |
Group Chat Server |
8 cores |
8 GB |
20,000 |
4 cores |
8 GB |
10,000 |
File Server |
4 cores |
4 GB |
80,000 |
2 cores |
3 GB |
40,000 |
Managing Your Virtual Environment
We recommend you use Microsoft System Center Virtual Machine Manager (VMM) to manage your virtualized Lync Server topology.
By using VMM, you do not need to use Terminal Services or Remote Desktop Services for the virtual machine management. Additionally, by using VMM you can view and manage performance, and other components such as disk space. You can also save a virtual machine as a template for creating new instances.
VMM uses Windows PowerShell, so you can create VMM Windows PowerShell scripts that integrate with Lync Server Management Shell to manage Lync Server.
For details about VMM, see the System Center Virtual Machine Manager website at https://go.microsoft.com/fwlink/p/?LinkId=202887.
Getting Started Using VMM
To get started using VMM to manage your virtualized Lync Server topology, do the following:
In VMM, create a new host group named
LS 2010.In the Actions pane, click Add Host.
If your virtual environment is part of your Active Directory domain, select that option. Otherwise, select the Windows Server-based host on a perimeter network, and click Next.
Install a VMM Agent on the host server. If the host server is on a perimeter network, you must create a security key, which must then be available to the VMM Administrative Console.
Go back to the VMM Administrative Console and click Add Host.
Specify the machine name and the domain/machine name and security key, making sure that VMM can find the host, and then click Next.
After the host has been added, the four virtual machines should be available. In the VMM Administrative Console, click the Virtual Machines button.
You will now see the Virtual Machines view, with the four virtual machines running Lync Server listed.
Using System Center Operations Manager
You can use Microsoft System Center Operations Manager (formerly Microsoft Operations Manager) to monitor your virtualized topology, just as you can with a physical topology. If you do so, install System Center Operations Manager R2 first, add the Lync Server Operations Manager pack, and then integrate it with VMM.
For details about integrating System Center Operations Manager with VMM, see "How to Integrate Operations Manager with VMM 2008 R2" at https://go.microsoft.com/fwlink/p/?LinkId=201214.