Server virtualization Lync Server 2010

Server Virtualization in Microsoft Lync
Server 2010

Last updated 2/18/2011

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Table of Contents
Summary.....................................................................................................................................................1
Glossary.......................................................................................................................................................2
Introduction.................................................................................................................................................5
1.1 What is Virtualization?......................................................................................................................5
1.2 Why Virtualize?.................................................................................................................................5
Virtualization in Lync Server 2010...............................................................................................................7
1.3 Terminology......................................................................................................................................7
1.4 Supported Functionality ...................................................................................................................8
1.5 Hypervisors.......................................................................................................................................8
1.5.1 Validated Hypervisors.................................................................................................................8
1.5.2 Other Hypervisors.......................................................................................................................9
1.5.3 Unsupported Hypervisors...........................................................................................................9
1.6 Guest Operating System Requirement..............................................................................................9
1.7 Virtualized Lync Server Deployment General Considerations...........................................................9
1.7.1 Mixing Physical and Virtual Servers Running Lync Server 2010..................................................9
1.7.2 Spreading Lync Server Workloads on Different VM Hosts..........................................................9
1.7.3 High Availability through Virtualization....................................................................................10
1.7.4 Quick Migration and Live Migration Support............................................................................10
1.7.5 Dynamic Memory Support........................................................................................................10
Typical VM Host Configurations.................................................................................................................10
1.8 VM Host Server Configuration........................................................................................................11
1.9 VM Guest Operating System and Application Storage Configuration.............................................12
1.10 Small VM Host Configuration .......................................................................................................12
1.11 Medium VM Host Configuration ..................................................................................................13
1.12 Large VM Host Configuration .......................................................................................................14
1.13 VM Host Networking Considerations............................................................................................16
Virtualization Configuration Guidance.......................................................................................................16
1.14 Applications Running in Host Root Partition.................................................................................16
1.15 Guest Virtualized Storage.............................................................................................................17
1.15.1 Disk Types...............................................................................................................................17
1.15.2 Mapping of Storage to VM Guests..........................................................................................17
1.15.3 VM Guest Storage Recommendations by Workload...............................................................17

1.16 Other VM Guest Configuration Settings........................................................................................19
1.16.1 Guest Operating System.........................................................................................................19
1.16.2 Network adapter.....................................................................................................................19
1.16.3 Ratio of Physical to Virtual CPUs.............................................................................................19
1.16.4 Support of VM Image Templates............................................................................................20
1.16.5 Disable Virtual DVD/CD Drives in Guest Operating System.....................................................20
Scale Comparison of Virtualized and Physical Lync Server Roles...............................................................20
1.17 CPU...............................................................................................................................................20
1.18 Memory........................................................................................................................................20
1.19 Scale Comparison Table Physical-Virtual.......................................................................................21
1.19.1 Maximum Conference Size Physical-Virtual............................................................................22
1.19.2 Stand-alone A/V Conferencing Server Recommendation Physical-Virtual..............................22
Sample Lync Server Virtualized Topologies................................................................................................22
1.20 Virtual Enterprise Edition Deployment A......................................................................................22
1.21 Virtual Enterprise Edition Deployment B......................................................................................23
1.22 Mix Virtual/Physical Enterprise Edition Deployment....................................................................25
1.23 Virtual Standard Edition Deployment..........................................................................................26
Test Results................................................................................................................................................27
Measuring Performance on Virtual Lync Server 2010................................................................................28
1.24 Performance Indicators.................................................................................................................28
1.24.1 Processor and Percentage of Processor Time.........................................................................28
1.24.2 Network Interface...................................................................................................................28
1.24.3 Memory..................................................................................................................................28
1.24.4 Databases................................................................................................................................28
1.24.5 SIP...........................................................................................................................................28
Appendix A: How to Enable VMQ on Intel Network Adapter....................................................................30
Appendix B: How to Increase Send/Receive Buffers on Intel Network Adapter........................................31
Appendix C: Changing the Bandwidth Limit for Application Sharing.........................................................32
Appendix D: Performance Counters..........................................................................................................33
1Lync Server 2010 Performance Counter Reference.................................................................................33
1.25 All Servers.....................................................................................................................................33
1.26 Front End Servers..........................................................................................................................34
1.27 Edge Server...................................................................................................................................37
1.28 Back End Server............................................................................................................................39
1.29 Mediation Server..........................................................................................................................40

1.30 Audio/Video Conferencing Server.................................................................................................41
1.31 Establishing Performance Baselines..............................................................................................41
1.31.1 Resource Utilization Baseline Tests.........................................................................................41
1.31.2 User Load Baseline Tests.........................................................................................................42
1.31.3 Multipoint Conferencing Unit (MCU) Resource Utilization Baseline Tests: (Monitor on All
MCUs)................................................................................................................................................42

Summary
Virtualization is a powerful technology that enables IT departments to reduce costs and improve
operational efficiency. Virtualization is increasingly being seen as a way to allocate resources
smartly, and consolidate environments. Building on the efforts taken in Microsoft® Office
Communications Server 2007 R2, Microsoft® Lync™ Server 2010 communications software provides
a wide range of server virtualization capabilities to reduce total cost of ownership (TCO). This
document outlines a series of best practice recommendations for running Lync Server 2010 in a
virtualized environment.

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Server Virtualization in Microsoft Lync Server 2010

Figures
Figure 1 Small VM host configuration diagram........................................................................................13
Figure 2 Medium VM host configuration diagram...................................................................................14
Figure 3 Large VM host configuration diagram........................................................................................15
Figure 4 Virtual Enterprise Edition deployment A....................................................................................23
Figure 5 Virtual Enterprise Edition deployment B....................................................................................24
Figure 6 Mixed virtual-physical Enterprise Edition deployment..............................................................25
Figure 7 Virtual Standard Edition deployment.........................................................................................26
Figure 8 Advanced tab of Network Adaptor Properties, showing Virtual Machine Queue setting..........30
Figure 9 Advanced tab of Network Adapter properties, showing Receive Buffers property...................31

Tables
Table 1 Supported virtualized Lync Server roles and workloads ...............................................................8
Table 2 VM host configuration categories ..............................................................................................11
Table 3 VM host hardware base configuration........................................................................................12
Table 4 VM guest storage configuration .................................................................................................12
Table 5 VM guest virtual storage options ...............................................................................................17
Table 6 VM guest storage sizing recommendations.................................................................................18
Table 7 Virtual-physical scale comparison table......................................................................................22

Glossary
The following are phrases and acronyms used throughout this document.
Phrase/Acronym Meaning
Standard Edition server Lync Server 2010, Standard Edition is designed for small organizations,
for pilot projects, or for branch sites within larger organizations. It
enables all of the features of Lync Server 2010, in addition to the
necessary databases, to run on a single server. Lync Server 2010
Standard Edition does not provide a true high availability solution.
Front End Server Lync Server 2010, Front End Server is the core server role of an
Enterprise Edition pool, and performs the basic Lync Server 2010
functions. It is one of two server roles required to be in any Lync Server
2010, Enterprise Edition deployment.
Enterprise Edition pool Lync Server 2010 Enterprise Edition is a collection of Front End Servers.
Enterprise pools with two or more Front End Servers provide high
availability, and allow scale out to a total of 10 Front End Servers within
a pool. Enterprise pools allow separation of A/V Conferencing Server

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components.
Back End Server Lync Server 2010, Back End Server is a core server role, and hosts the
Microsoft® SQL Server™ databases used by the Lync Server Front End
Server. The Back End Server is the second of two server roles required
to be in any Lync Server 2010 Enterprise Edition deployment. Back End
Servers can be deployed on a single server running SQL Server, or on a
SQL Server cluster.
Pool A pool is a set of identically configured servers running Lync Server that
work together to provide services for a common group of users. A pool
provides scalability and resiliency for the hosted workloads and
functions.
A/V Conferencing Server Lync Server 2010, A/V Conferencing Server provides audio/video (A/V)
conferencing functionality to a deployment. It can be collocated with
the Lync Server 2010 Front End Server, or deployed separately as a
single server or Lync Server 2010 A/V Conferencing Server pool. For
best performance, A/V Conferencing Server should be deployed
separately to the Front End Server. Standard Edition server cannot
utilize a stand-alone A/V Conferencing Server. AV Conferencing Servers
are deployed as a single server or a pool of servers. No more than one
A/V Conferencing pool is supported per site.
Edge Server Lync Server 2010, Edge Server enables users to communicate and
collaborate with users outside an organization’s firewalls.
Edge Servers are deployed as a single server or a pool of servers.
Monitoring Server Lync Server 2010, Monitoring Server collects data about the quality of
network media in both Enterprise Voice calls and A/V conferences, as
well as call detail records (CDRs). Monitoring Server is typically
collocated with the Microsoft Lync Server 2010, Archiving Server. A SQL
Server Back End Server is required to implement a Monitoring Server.
Monitoring Server can be deployed only as a single server.
Archiving Server Lync Server 2010, Archiving Server enables the archiving of instant
messaging (IM) communications and meeting content for compliance
reasons.
A SQL Server Back End Server is required to implement Archiving.
Archiving Server can be deployed only as a single server.
Director The Microsoft Lync Server 2010, Director can authenticate Lync Server
requests and redirects users to the their respective home pool. The
Director role is most useful in deployments that enable external user
access where the Director can authenticate requests before sending
them on to an internal server. Directors can also improve performance
in organizations with multiple Front End pools. Directors are deployed
as a single server or a pool of servers.
Application Sharing service The Application Sharing service, hosted on a Front End Server.
Mediation Server The Microsoft Lync Server 2010, Mediation Server is a necessary
component for implementing Enterprise Voice and dial-in conferencing.
Mediation Server translates signaling and, in some configurations,

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media between your internal Lync Server infrastructure and an public
switched telephone network (PSTN) gateway or a SIP trunk. Mediation
Server can be collocated with the Front End Server, or can be installed
as a stand-alone server for better performance. A stand-alone
Mediation Server is recommended if Media Bypass is not available.
Stand-alone Mediation Servers are deployed as a single server or a pool
of servers.
Multi-modal Conference A conference using all modalities of Lync Server, including: application
sharing, Voice over Internet Protocol (VoIP), video, instant messaging,
dial-in conferencing, and web conferencing.
VM A virtual machine is an instance of a guest operating system (running
Windows Server® 2008 R2) running on a server running a hypervisor,
such as Microsoft® Hyper-V™ or VMware ESX.
Site Lync Server 2010 sites are defined as a location-based or logical
grouping of collection of Lync Server 2010 components. A site is a set of
computers that are well connected by a high-speed, low-latency
network, such as a single local area network (LAN) or two networks
connected by a high-speed fiber optic network. Note that Lync Server
sites are a separate concept from Active Directory® Domain Services
(AD DS) sites and Microsoft® Exchange Server sites. Your Lync Server
sites do not have to correspond to your Active Directory sites.
Hypervisor A native hypervisor runs directly on the host hardware on the lowest
level (Ring -1, below kernel mode), and provides abstraction to allow
multiple operating systems to run concurrently on a host computer, a
feature called hardware virtualization. The hypervisor provides the
guest operating systems with a virtual operating platform and monitors
the execution of the guest operating systems.

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Introduction
1.1 What is Virtualization?
Virtualization, in its simplest form, provides a layer of abstraction between the hardware and operating
system, and allows multiple operating system instances to share the same hardware. Server
virtualization allows multiple operating systems (or “virtual machines”) and applicable workloads to
share the resources of a single server. The main benefits of virtualization are improved resource
utilization, and the ability to relocate virtual machines to different hosts, typically reducing the number
of physical servers needed.

1.2 Why Virtualize?
In today’s competitive environment, organizations are increasingly dealing with concerns around
reducing infrastructure costs while accurately forecasting operational expenditure, creating more value
by providing faster but lower-cost services, and increasing operational efficiency at the same time. A
well-managed IT environment that is efficient, reliable, and easily managed is essential to successfully
meeting the above goals of the organization. Lync Server, with its server virtualization capabilities, helps
companies achieve this goal by providing the following benefits:
• Reduced Total Cost of Ownership

o Leverage existing resources with server consolidation

o Increase space utilization with reduced number of physical servers

o Reduce power consumption and cooling requirements

o Decrease hardware maintenance and training costs

o Provide an abstraction of operating system and workloads from actual physical hardware

o Reduced Time to deploy

o Minimize service disruption and increase service levels

o Provide capacity on demand in response to changing business needs

o Speed up server deployment by duplicating a standard virtual server

• Increased operational efficiency

o Improve business continuity with high availability of hardware and applications

o Increase operational flexibility with dynamic resource management and server provisioning

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o Improve server to admin ratio

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Virtualization in Lync Server 2010
Microsoft has made significant investments in providing extensive virtualization support for Lync Server
across a fully distributed topology. Lync Server can be virtualized by using Windows Server 2008 R2
Hyper-V, or other virtualization solutions that have been tested by Microsoft. For more details, see
“Windows Server Virtualization Validation Program” at http://go.microsoft.com/fwlink/?linkid=200511.
Due to limitations such as packet loss, delay, jitter, and clock skew, Office Communications Server 2007
R2 could only virtualize a few workloads such as Presence and IM. Lync Server 2010 now also supports
server-side virtualization of real time media, thus enabling conferencing and voice workloads to be
virtualized.
Lync Server enables the following workloads to be virtualized:
• Instant Messaging (IM)
• IM conferencing
• Presence
• Enterprise Voice (PSTN)
• Audio Conferencing
• Video Conferencing
• Web Conferencing
• Application Sharing
• Remote Access, Federation (Edge Server)
• Response Group service

Virtualized Lync Server deployment can be considered for all sizes of deployment: From small single-site
deployments, to large multi-site enterprise implementations.
This document provides details on:
• Best practice guidelines for deploying a virtualized Lync Server topology
• Typical VM host configurations
• VM guest configuration best practices based on the workload
• Scale comparison of virtualized and physical Lync Server roles
• Measuring Performance
Note: This document does not cover client virtualization scenarios such as application virtualization or
remote desktop scenarios for the Lync client.

1.3 Terminology
Throughout this document, the following statements will be used:
• Recommended: A recommended configuration or setting that has been explicitly validated, or
follows the industry best practice standards.

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• Not recommended: A configuration or setting that is not recommended in a production
deployment, based on the industry best practice standards, or that has been specifically
identified as a potential problem in a virtualized Lync deployment.
• Not supported: A configuration, feature, or setting that must not be implemented in a
virtualized Lync Server deployment. Running unsupported deployment may negatively impact
functionality or performance of a Lync Server deployment.

1.4 Supported Functionality
Table 1 lists the server roles and corresponding features that are tested and supported in a virtualized
site.
Role Supported Supported Features

Enterprise Front End Yes Registration, Presence, IM, Enterprise
Voice, audio/video
Standard Edition Server Yes Registration, Presence, IM, Enterprise
Voice, audio/video, SQL Store
SQL Server Back End Yes SQL Store
Server
File Store Yes File server
Edge Server Yes Remote Access
A/V Conferencing Server Yes Audio/video
Mediation Server Yes Enterprise Voice
Director Yes Authentication, Redirection
Monitoring Server Yes Monitoring service, QoE, and call detail
records
Archiving Server Yes Archiving service
Survivable Branch Office No Registration, Enterprise Voice
Appliance (OEM appliance)
Survivable Branch Office Yes Registration, Enterprise Voice
Server
(non-OEM server)
Table 1 Supported virtualized Lync Server roles and workloads

Like a physical Lync Server, virtual Lync Server deployments will integrate with Microsoft Exchange
Server 2010 to provide a Unified Messaging solution. Deployment of Lync Server in a virtual
environment is described in this white paper. For details about deploying Exchange 2010 Unified
Messaging, see “Understanding Unified Messaging Deployments” at http://go.microsoft.com/fwlink/?
LinkId=210839.

1.5 Hypervisors
1.5.1 Validated Hypervisors
• Windows Server 2008 R2 Hyper-V (For details about hotfix, see Microsoft Knowledge Base
article 981836, “Network connection is lost on a Windows Server 2003-based Hyper-V VM” at
http://go.microsoft.com/fwlink/?LinkId=201212)

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• Microsoft® Hyper-V™ Server 2008 R2 Hyper-V (For details about hotfix, see Microsoft
Knowledge Base article 981836, “Network connection is lost on a Windows Server 2003-based
Hyper-V VM” at http://go.microsoft.com/fwlink/?LinkId=201212)

• VMware ESX 4.0

1.5.2 Other Hypervisors
Other Hypervisor implementations that have been validated through the Windows Server Virtualization
Validation Program.
Note: Lync Server is a real-time application workload which requires high-performance I/O (Network
and Storage) which some hypervisor implementations may not be able to deliver. We recommend
validating a deployment by using synthetic load tools.

1.5.3 Unsupported Hypervisors
Although Hyper-V was available as a role in Windows Server 2008, that release is not supported. A
number of enhancements that are critical for running virtualized Lync Server media workloads were
implemented with Windows Server 2008 R2 to address network packet loss.

1.6 Guest Operating System Requirement
Windows Server 2008 R2 is required guest operating system. Critical network performance
improvements are only available in the Windows Server 2008 R2 operating system.
Windows Server 2008 SP2 is not supported as a guest operating system.

1.7 Virtualized Lync Server Deployment General Considerations
1.7.1 Mixing Physical and Virtual Servers Running Lync Server 2010
Generally physical and virtual servers can be combined in a deployment, with the following limitations:
Mixed virtual and physical servers within the same pool are not supported. A pool1 of Lync Server roles
must be deployed as a homogenous set of servers (either physical or virtual) which roughly provide the
same amount of resources. For virtualized deployments, ensure that the virtual machines are hosted in
a way that equal resources are available to each guest in the pool. Lync Server does not perform load-
based load balancing with the exception of the A/V conferencing workload. Note that a virtual Front End
Server and a physical SQL Server Back End Servers are explicitly supported.
Balanced end-to end-performance is required. When sizing a virtualized Lync Server deployment, use
the guidance provided in this document to size each role adequately, and perform tests using the
synthetic load tools available to validate that no bottlenecks exist.

1.7.2 Spreading Lync Server Workloads on Different VM Hosts
If you are implemented a highly available, virtualized, Lync Server deployment consider spreading
similar workloads to different VM hosts. For example, do not run all of the Front End Servers on the
same VM host because you could potentially lose the complete pool if there is a failure on an individual
1
A pool is defined as a Lync Server pool with more than two servers including the follow Server roles: Enterprise
Edition Front End Server, Director, Mediation Server, A/V Conferencing Server, and Edge Server.

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VM host. Consider recovery of virtual machines on a different host as tool to limit the outage, but not as
a tool to implement High Availability (also see next bullet).

1.7.3 High Availability through Virtualization
Virtualizing a Lync Server deployment is not a replacement for implementing High Availability:
Implement a pool of Lync server components (such as an Front End pool or Edge pool with two
or more servers), as well as a clustered SQL Server Back End Server in order to achieve the best
possible High Availability even in a virtualized setup. Migration to the next available virtual
machine host is a tool to mitigate the duration of downtime, however does not provide the best
High Availability solution for Lync Server.

1.7.4 Quick Migration and Live Migration Support
Quick Migration and Live Migration with Lync Server 2010 workloads have not been validated by the
product group at this point. Future updates of this white paper will provide more guidance.
Considerations for migrating Lync Server workloads:
• Front End Servers: Using draining prior to migration to minimize any client impact. Clients will
disconnect from active sessions, such as active conferences, during migration.
• Migrating Front End Server or A/V Conferencing Server while a conference is progress: The delay
will cause all clients to disconnect and the conference is recreated on another Front End Server,
or A/V Conferencing Server.
• SQL Server Back End Server workload: While migration of the SQL Server back end VM, the Front
End Servers will switch to resiliency mode until the migration is completed, and should
reconnect.
• Depending on the time a migration takes, and what workloads are concurrently migrated,
clients may connect to the backup registrar pool.

Live Migration of Lync Server workloads have not been validated, and is not supported (Applicable to
Hyper-V Live Migration, and VMware Vmotion). Specifically, it has not been validated what the client
experience would be if a live migration is performed on a Lync Server workload running an active
conference.

1.7.5 Dynamic Memory Support
Windows Server 2008 R2 Hyper-V SP1 (Service Pack 1) will provide support for Dynamic Memory (for
details, see “Implementing and Configuring Dynamic Memory” at http://go.microsoft.com/fwlink/?
LinkId=211071). Dynamic memory has not been validated with Lync Server 2010 workloads, and specific
guidance cannot be provided.

Typical VM Host Configurations
Glossary:
• Direct Attach Storage (DAS): Disk storage local to host, not shared.
• Storage Area Network (SAN): Storage devices accessible through a dedicated network.
• Internet Small Computer System Interface (iSCSI): IP-based storage networking
standard, typically using Ethernet.

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• Fiber channel (FC) : Network technology primarily for storage networking.
• MPIO = Multi-path IO: Redundant network path to a shared storage device.
• Virtual Machine Queue (VMQ): Hardware virtualization technology for the efficient
transfer of network traffic to a virtual machine.
• Gigabit Ethernet (GbE): Type (Ethernet) and speed (units of Gigabit per second) of a
network infrastructure.
• Serial Advanced Technology Attachment (SATA): Computer bus interface for mass
storage attachment.
• Serial Attached SCSI (SAS): Computer bus interface for mass storage attachment.
• Solid state drive (SSD): A data storage device using solid-state memory.
• Logical unit number or LUN: A number used to identify a logical unit in a SAN or other
storage devices. Mostly used to refer to a logical disk in a SAN.

Hardware vendors typically provide guidance on what type of servers, storage, and networking
components are recommended for production-quality VM host configurations. The following
section provides a generic overview of what configurations are suitable for deploying a virtual Lync
Server deployment, and what type of configurations should be avoided.

With the context of this document VM host configurations are defined in the following scale, and
are outlined in more detail below
Size VM Host Configuration
Small Single VM host with direct attached storage (DAS)

Medium 4-12 VM hosts with shared storage (iSCSI SAN) multi path I/O (MPIO)
Large 12-48 VM hosts with fiber connected shared storage (FC SAN multi path I/O)
Table 2 VM host configuration categories

1.8 VM Host Server Configuration
The follow table represents a recommended hardware base configuration for a VM host as of Q4/2010.
Component Spec
Server Enterprise-grade server, with a minimum of 2 CPU sockets (or more)
CPU Intel Xeon 5500 series or AMD Opteron 6100 series (2 GHz+)
CPUs supporting NPT/EPT (Nested Page Tables/Extended Page Tables)
Network adapter Dual (or more) 1 GbE or 10 GbE adapter (with VMQ support is recommended
for 10 GbE network adapternetwork adapter). Note: Network adapter chipsets
from Intel, Broadcom, and other vendors support VMQ.
Storage Two or more SATA or SAS HDD 10k rpm or higher (DAS), or equivalent storage,

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RAID 1 (VM host operating system usage), or equivalent SSD
Memory 32GB+ PC2-6400 DDR2, or PC3-8500 DDR3 Memory (or faster), must be ECC
compliant
Table 3 VM host hardware base configuration

1.9 VM Guest Operating System and Application Storage Configuration
Storage recommendations are based on typical enterprise-grade traditional hard disk drives, or
equivalent enterprise-grade solid state drives (SSDs). Typical protocols for Storage Area Networks are
iSCSI, Fiber Channel, or other equivalent solutions.
Type Spec
DAS Direct Attached Storage with SAS (15k or 10k rpm) or SATA (7.2k rpm) drives
iSCSI SAN Storage Array Network with 1 GbE or 10 GbE iSCSI storage with enterprise class
SAS (15k rpm) drives, or equivalent SSD drives. 2+ GB cache.
FC SAN Fiber connected Storage Array Network with 4, or 8Gbps Fibre Channel with
enterprise class SAS (15k rpm) drives, or equivalent SSD drives. 4+ GB cache.
CSV Cluster Shared Volume (CSV) is a volume that is simultaneously available to
directly read from and write.
Table 4 VM guest storage configuration

1.10 Small VM Host Configuration

A single VM host with direct attached storage configuration.

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Figure 1 Small VM host configuration diagram

Recommended networking:
• Dual network adapter/host: 1 network adapter reserved for host access, 1+ network
adapter for shared VM guest application workload.
• network adapter speed: 1 GbE or 10 GbE (VMQ)
Recommended storage:
• Dedicated spindle for VM host, as well as a dedicated spindle for each VM guest virtual
drive
Not recommended:
• 100 Mbps network adapters
• Single network adapter (for VM host and VM guest application workload)
• Shared spindles between host and guests, or between guests

1.11 Medium VM Host Configuration
Multiple VM host with shared storage (SAN) attached through iSCSI.

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Figure 2 Medium VM host configuration diagram

• 3 network adapters/host: 1 network adapter reserved for host access, one 1 for shared
VM guest application workload, 1 (or more) dedicated to iSCSI SAN access
• MPIO is recommended for network access to SAN
• Separation of application and iSCSI traffic (dedicated iSCSI segment)
• Network adapter speed: 1 GbE or 10 GbE.
• Implement VLANs to isolate network traffic
• Dedicated SAN LUN for each VM guest virtual drive (VHD or passthrough)
• Cluster Shared Volume (CSV)
Not recommended:
• Host with less than 3 network adapters
• Shared Host/Application/iSCSI network adapter configurations
• Shared LUNs for VM guest or application workloads

1.12 Large VM Host Configuration
Multiple VM host with shared storage (SAN) attached through Fiber Channel. Multiple network
adapter (network adapter teaming) for load balanced guest network access. Dedicated network
adapter for host-to-host communication (VM quick migration).

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Figure 3 Large VM host configuration diagram

• 4+ network adaptera/host: 1 network adapter reserved for host access, one 2 network
adapters for shared VM guest application workload, 1 network adapter for VM host to
host communication
• Fiber Channel (4 Gbps or 8 Gbps),
• Network adapter speed: 1 GbE or 10 GbE (10 GbE recommended)
• Guest network adapter teaming (IEEE 802.3ad, network adapter teaming). Network
adapter fault tolerance, and link aggregation
• Redundant network adapter and Fiber channel controllers, MPIO is recommended
• Alternatively to dedicated Fiber Channel
• Implement VLANs to isolate network traffic
• Dedicated SAN logical unit number (LUN) for each VM guest virtual drive (VHD or
passthrough)
• Cluster Shared Volume (CSV)Redundant controllers in SAN
Not recommended:
• Shared host/application network adapter configurations
• Shared LUNs for VM guest or application workloads

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1.13 VM Host Networking Considerations
Important Note: Lync Server media workloads, such as A/V and application sharing require more
bandwidth that other typical server workloads (such as email or SQL Server database). The Lync media
workloads are also more vulnerable to high latency and packet loss problems.
While designing a virtualized Lync deployment it important to take networking contention into account.
Networking considerations:
• VM host must have at least one dedicated network adapter for the Lync Server workload.
Shared usage with the VM host, or specifically with SAN access is not recommended.
• A Lync Server Media workload (primarily Front End Servers and A/V Conferencing Servers), can
reach a peak network utilization of more than 500 Mbps (0.5 Gbps).
• If a specific VM host is targeted to host multiple guest VMs running Lync media workloads,
ensure that the host network adapter is sized accordingly. To mitigate bottlenecks consider
higher speed network adapters (such as 10 GbE), or multiple network adapters using link
aggregation (network adapter IEEE 802.3ad), for example a 3 x 1 GbE network adapter in a
network adapter teamed setup. For details, see Mircosoft Knowledge Base article 968703,
“Microsoft Support Policy for NIC Teaming with Hyper-V” at http://go.microsoft.com/fwlink/?
LinkId=211073.
• Enable VLAN tagging on the host network adapter, and implement (multiple) VLANs on the
guests to optimize the network traffic for the various workloads, such as Front End Server to
Client/AVMCU, and Front End Server to SQL Server Back End Server.
• Implement MPIO (Multi-Path IO) to your storage Back End Server.
• Network adapter supporting VMQ: Enable Windows Server 2008 R2 Hyper-V and enable VMQ
on the host network adapter. Note that not all network chipsets support VMQ. Current network
adapter chipset vendors with VMQ support are Intel, Broadcom, and other vendors.

Virtualization Configuration Guidance
The VM guest configurations described in this section are based on virtualization best practices for
general enterprise scale application workloads. While concepts and implementation details discussed
here are specific to Hyper-V on Windows Server 2008 R2, similar concepts and features are available
with other virtualization platforms.

1.14 Applications Running in Host Root Partition
• Running application in the VM host root operating system is not recommended.
• If antivirus software is deployed, ensure that the necessary scanning exceptions are
implemented (such as files, folders, and processes ). For details, see Microsoft Knowledge Base
article 961804, “Virtual machines are missing in the Hyper-V Manager Console or when you
create or start a virtual machine, you receive one of the following error codes: “0x800704C8”,
“0x80070037” or “0x800703E3” at http://go.microsoft.com/fwlink/?LinkId=210844.
• For further recommendations, see “Planning for Hyper-V Security” at
http://go.microsoft.com/fwlink/?LinkId=210845.

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1.15 Guest Virtualized Storage
The following table describes the different types of virtual hard drives in the guest. For best
performance results, the a virtual disk has to reside dedicated physical disks, or on a dedicated logical
unit on a SAN.

1.15.1 Disk Types

Type Recommended Comment
Dynamic Disk No Dynamic Disk VHDs are not recommended for production servers.
Fixed Disk Yes Fixed Disk VHDs must be placed on a dedicated spindle in Direct
Attached Storage, or on a dedicated LUN (Logical Unit) in a SAN.
Passthrough Yes Passthrough disks are physical disks, or LUNs on a SAN which are
Disk exposed to the host and accessed by the guest directly. The
performance is typically slightly higher than fixed disks.
Table 5 VM guest virtual storage options

For details, see “Planning for Disks and Storage” at http://go.microsoft.com/fwlink/?LinkId=210846.

1.15.2 Mapping of Storage to VM Guests
Hyper-V offers a number of different ways to expose a drive to a VM guest operating system. The
appropriate method depends on a number of factors, such as if the storage is locally attached, or on a
SAN, and there are no specific preferences from a Lync Server visualization perspective.

Common best practices:
• VM guest operating system boot drive must be mapped as a virtual IDE drive. SQL Server
workloads use a virtual IDE drive for the operating system, and SQL Server binaries, and virtual
SCSI controllers to map SQL Server log and SQL Server data drives
• iSCSI targets directly exposed to the VM guest is typically implemented if VMs need to be moved
between VM hosts. Here the guest operating system drive on the SAN and the guest specific
data drives will automatically be accessible to the guest after the move. If VMs are moved, it is
required that guest storage is located on a shared storage attached using either iSCSI, for Fibre-
Channel.

1.15.3 VM Guest Storage Recommendations by Workload

1.15.3.1 Guest Storage Sizing Recommendations
Storage type Size
Guest VM operating system with Lync Server installed (including 50 GB
paging file)
SQL Server storage drives 30-100 GB*

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File storage drives 30 GB – 500 GB*
Table 6 VM guest storage sizing recommendations

* Size depends on scale of deployment depending on features such as meeting content archiving that
are used in the Lync Server deployment.

1.15.3.2 Lync Server Workloads Storage
Note: The following recommendations ask for a single VHD or physical disk for the VM guest operating
system and installed application. We also recommend separate operating system and application
(binary) installation virtual hard drives (VHD) are recommended. The decision to implement a separate
dedicated operating system VHD may depend on your preferences for your actual virtualized
deployment.

Single virtual drive in guest VM , attached as a virtual IDE using a Fixed Disk, or Passthrough Disk. The
virtual drive is placed on a dedicated physical spindle, or a dedicated LUN in a SAN. Workloads:
• Front End Server
• Director
• Edge Server
• Stand-alone Mediation Server
• Stand-alone A/V Conferencing Server
• Archiving/Monitoring Server
• Survivable Branch server (not applicable to OEM Survivable Branch Appliance)

Two virtual drives in guest VM, attached as virtual IDE (optionally second as virtual SCSI) using Fixed
Disk, or Passthrough Disk. The virtual drives are placed on dedicated physical spindles, or a dedicated
LUN in a SAN. Workload:
• Standard Edition server

1.15.3.3 SQL Server Workloads Storage
All virtual drives are placed on dedicated physical spindles, or a dedicated LUN in a SAN. This is especially
critical for the SQL Server storage virtual drives.

SQL Server Back End Server to a Front End pool
Four virtual drives in guest VM. Boot operating system drive attached as a virtual IDE using Fixed Disk.
Three drives for SQL Server storage attached using virtual SCSI attached as a Passthrough Disk. However
with slightly lower performance requirements, Fixed Disk for SQL Server storage is also acceptable.
The three SQL Server storage drives map the following way: Rtcdyn log, Rtc log, and all other databases
and logs.

SQL Server Back End Server for Archiving and Monitoring

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Three virtual drives in guest VM. Boot operating system drive attached as a virtual IDE using Fixed Disk.
Two drives for SQL Server storage attached using virtual SCSI attached as a Passthrough Disk. However
with slightly lower performance requirements, Fixed Disk for SQL Server storage is also acceptable.
The two SQL Server storage drives map the following way: Log files, DBs files.

Important: Setting up databases in Lync Server on a virtualized SQL Server requires the use of the Install-
CsDatabase cmdlet with the DatabasePath parameter set to explicitly allocate the designated SQL Server
storage virtual drives. We do not recommend placing database or log files on the guest operating system
drive.
Important: We do not recommend collocating back-end databases and Archiving and Monitoring
databases into the same virtual SQL Server workload.

1.15.3.4 File Storage
Two virtual drives in guest VM, with the guest operating system drive attached as virtual IDE using
Fixed Disk, and the second drive attached as virtual SCSI using a Passthrough Disk (acceptable Fixed
Disk). The second drive is used for the Lync Server file share.
The virtual drives are placed on dedicated physical spindles, or a dedicated LUN in a SAN.
Note: For more details and recommendations about storage options, see “Storage options for Windows
Server 2008 Hyper-V” at http://go.microsoft.com/fwlink/?LinkId=210858.

1.16 Other VM Guest Configuration Settings
1.16.1 Guest Operating System
Windows Server 2008 R2 is the required guest operating system. Windows Server 2008 SP2 is not
supported.

1.16.2 Network adapter
• Always use the synthetic VM network adapter in the guest operating system. The use of the
legacy network adapter is not supported for a guest operating system running a Lync Server
media workload.
• Use IP version 4 (IPv4) only in the VM guest and VM host. Disable IPv6 on both the guest and
host for improved performance.

1.16.3 Ratio of Physical to Virtual CPUs
Do not oversubscribe physical to virtual CPUs, specifically:
• Oversubscription of CPU cores on the host running virtualized Lync Server media workloads is
not supported.
• Oversubscription of CPU cores on the host is not recommended when running other non-media
virtualized Lync Server workloads (such as Director and Archiving and Monitoring Server), or
supporting virtualized storage workloads (SQL Server or file server).
Note: Virtual machine reserved allocations are not explicitly necessary. If CPU oversubscription is
implemented, consider allocating virtual machine reserves for critical workloads such as the SQL Server
Back End Server.

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1.16.4 Support of VM Image Templates
Lync Server 2010 does not support sysprep, which is applicable also to Microsoft® SQL Server 2008
Express, which is installed on each Lync Server role. This implies that a preconfigured generic Lync
Server VM image templates cannot be created.
We recommend the use of custom operating system templates with applicable operating system
prerequisites installed depending on the targeted workload, for example an operating system template
for Front End Servers containing Internet Information Services (IIS), Windows Media® Format Runtime,
Message Queuing (also known as MSMQ).
As a separate VM configuration step, Lync Server roles get deployed and activated after the guest
operating system is fully configured.

1.16.5 Disable Virtual DVD/CD Drives in Guest Operating System
If virtual DVD/CD drives are not required in the guest operating system, it is a best practice to disable
these drives for better performance.

Scale Comparison of Virtualized and Physical Lync Server Roles
1.17 CPU
We recommend an 8 CPU core (Enterprise class CPU) hardware profile for a physical Lync Server.
However, Hyper-V supports a maximum of 4 virtualized CPU core. Due to this resource constraint, a
virtualized Lync Server role can handle approximately 50% of the load compared to a physical server
running Lync Server and using the recommended hardware specifications.
In addition, a 10% virtualization overhead is deducted.

1.18 Memory
Required memory of a virtualized Lync Server 2010 role does not scale down in a linear way by 50%. A
recommendation per workload is provided in the table below.

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1.19 Scale Comparison Table Physical-Virtual
Standard User model with conferencing, PSTN conferencing, and Enterprise Voice
IM&P = IM and Presence
AS = Application Sharing
AV = A/V Conferencing (collocated if Front End Server)
EV = Enterprise Voice (Response Group Service/PSTN access), Mediation Server
Reg = Registrar (subset of IM&P)
AP = Access Proxy (Edge Server)
DP = Data Proxy (Edge Server)
MR = Media Relay (Edge Server)

Note: The Virtual Machine numbers are based on a 4 core CPU Virtual Machine.

Lync Server Role Features Physical Virtual
CPU Memory User CPU Memory User
Enterprise Edition IM&P 8 core 12 GB 20K 4 core 10 GB 12.5K
Front End Server
Enterprise Edition IM&P, AS, AV, EV 8 core 16 GB 5K 4 core 16 GB 2.5K
Front End Server
Enterprise Edition IM&P, AS, EV 8 core 12 GB 10K 4 core 11 GB 5K
Front End Server (8 Front End pool)
Enterprise Edition IM&P, AS, EV 8 core 12 GB 7K 4 core 11 GB 4K
Front End Server (single Front End
Server in pool)
Standard Edition IM&P 8 core 16 GB 25K 4 core 12 GB 12.5K
Front End Server
Standard Edition IM&P, AS, AV, EV 8 core 16 GB 5K 4 core 16 GB 2.5K
Front End Server
Director Reg 4 core 4 GB 20K 4 core 4 GB 10K
Monitor/Archiving 8 core 16 GB 230K 4 core 8 GB 110K
Server
A/V Conferencing AV 8 core 16 GB 20K 4 core 11 GB 10K
Server
Mediation Server* MS 8 core 16 GB 800 4 core 10 GB 400
concurrent concurrent
calls calls
Edge Server AP, DP MR 8 core 16 GB 15K 4 core 8 GB 7.5K

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Survivable Branch Reg, MS 2 core 2 GB 1K 2 core 2 GB 1K
Server
SQL Server Back 8 core 32 GB 80K 4 core 16 GB 40K
End Server (FE)
SQL Backend (M/A) 8 core 16 GB 230K 4 core 12 GB 115K
File Server 4 core 4 GB 80K 2 core 3 GB 40K
Table 7 Virtual-physical scale comparison table

* Stand-alone Mediation Server for deployments without Media Bypass

1.19.1 Maximum Conference Size Physical-Virtual
• Physical deployment: 250 users
• Virtualized deployment: 125 users (4 core CPU Virtual Machine)

1.19.2 Stand-alone A/V Conferencing Server Recommendation Physical-Virtual
Recommendation for deploying a dedicate stand-alone A/V Conferencing Server or pool separate from
an Enterprise Edition Front End pool:
• Physical Lync Server deployment: 10K or more users
• Virtual Lync Server deployment: 5K or more users (4 core CPU Virtual Machine)

Sample Lync Server Virtualized Topologies
Note: The diagrams below are examples, and it is not required to host a specific combination of VM
workload on any given VM. The example VM host specification here is a 16 core server, with 64 GB
of memory.

1.20 Virtual Enterprise Edition Deployment A
All virtualized topology with eight Front End Servers, four A/V Conferencing Servers, one SQL Server
Back End Server, one SQL Server for archiving and monitoring, one Archiving and Monitoring Server
(collocated), one File Server, and – on a separate VM host in the perimeter network (also known as
DMZ) – two Edge Servers.
Scale: 40K users, default usage profile, all modalities

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Figure 4 Virtual Enterprise Edition deployment A

1.21 Virtual Enterprise Edition Deployment B
All virtualized topology with four Front End Servers, three A/V Conferencing Servers, one SQL
Server Back End Server, one SQL Server for archiving and monitoring, one Archiving and Monitoring
Server (collocated), one File Server, and (with VLAN into the perimeter network) single Edge Server.

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Figure 5 Virtual Enterprise Edition deployment B

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1.22 Mix Virtual/Physical Enterprise Edition Deployment
Mixed virtualized/physical topology with eight Front End Servers, four A/V Conferencing Servers,
one SQL Server Back End Server (physical Back End and Archiving and Monitoring Store in same SQL
Server instance), one Archiving and Monitoring Server (collocated), one File Server (physical), and
two Edge Servers (on physical server). Survivable Branch Server virtualized (example for single site),
and other workloads are running on the VM host in the branch.

Figure 6 Mixed virtual-physical Enterprise Edition deployment

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1.23 Virtual Standard Edition Deployment
All virtual Standard Edition deployment, single Standard Edition server, with Archiving and
Monitoring, SQL Server (Archiving and Monitoring), Edge Server (VLAN configuration to perimeter
network)

Figure 7 Virtual Standard Edition deployment

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Test Results
• Virtual Machine Queue (VMQ) should be enabled wherever supported by network adapters.
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
adapternetwork adapter, resulting in improved efficiency of network traffic.
VMQ requires support in the hypervisor, as well as using VMQ-enabled network adapternetwork
adapters (limited to Intel and Broadcom based network adapternetwork adapters). You can
enable this for each virtual machine using the hypervisor’s management console, assuming that
the host’s network adapternetwork adapter supports this.
For details about enabling VMQ, see Appendix A.
• Ensure that the latest network adapternetwork adapter driver from the hardware manufacturer
is installed.
• Increase the network adapternetwork adapter’s send/receive buffers to at least 1024 on any
network adapternetwork adapter dedicated to virtual machines. Increasing the send/receive
buffer allows the operating system greater time to process the network queue, and helps to
avoid packet loss. For details about how to do this, see Appendix B.

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Measuring Performance on Virtual Lync Server 2010
The testing described in the previous section required interpreting the Lync Server user model, and
understanding how to measure the performance of Lync Server. This section describes the user model
and how it was used to measure performance on virtual machines that are running Lync Server.
Additionally, this section describes the key performance indicators (KPIs) to monitor for virtual Lync
Server performance.

1.24 Performance Indicators
For details about specific performance counters and where to observe them, see Appendix D:
Performance Counters.

1.24.1 Processor and Percentage of Processor Time
In general, all processors and percentage of total processor time should be measured on each server.
Short CPU spikes of 70% or more for less than a few minutes is acceptable, however, the CPU should
typically be operating at less than 70% during peak load. If it is consistently higher, there could be more
users connected than usual, or some other change resulting in higher load. This indicates that the
process is overloaded, and more instances of the server are needed to handle that load.

1.24.2 Network Interface
The network adapternetwork adapters should be operating at no more than 80% capacity.

1.24.3 Memory
Pages/second indicates the total pressure on the server’s available memory.

1.24.4 Databases
• Queue Latency: The amount of time a request spends in the queue to the Back End Server.
If for any reason resources (such as disk, memory, network, and processor) on the Back End
Server are too high, the queue latency will also be high. Queue latency can also be high if there
is too much network latency between the Front End Server and the Back End Server.
• Sproc Latency: The amount of time it takes the Back End Server to process a request.
If both Sproc latency and Queue latency counters are high, then the most likely bottleneck is the
SQL Server back-end database. Check for disk IO contention first (see disk). SQL Server database
active transactions are a good indicator of which database is having more contention than
others.
• Page Life Expectancy: The server needs more RAM if this counter is a value fewer than 3600,
which indicates memory pressure by the system. Note: there should be few ‘reads’ on the
database drive if there’s sufficient memory because SQL Server should only be writing to the
database.

1.24.5 SIP
• Average Holding Time for Incoming Messages: If this counter is more than 10 seconds (12
seconds maximum), then the server goes into throttling mode and only allows one outstanding

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transaction per client connection. If this value goes down to 3 seconds, then the server allows
up to 20 outstanding transactions per client connection.
• Flow Controlled Connections: Whenever the number of transactions on a specific connection
exceeds the above threshold, the connection is marked as flow controlled and the server
doesn’t post any receives on it, and this counter is incremented.
• Local 503 Responses/sec: The HTTP 503 return code corresponds to server unavailable. There
shouldn’t be any of these responses on a healthy server in a steady state. There may be some
during ramp up, after a server has just been brought back online, but once all users reconnect
and the server reaches a stable state there should no longer be any of these responses.
• Local 504 Responses/sec: A few of these responses to clients are to be expected (for example,
when clients abruptly disconnect), but this counter mostly indicates connectivity issues with
other servers. This can indicate connection failures or delays connecting to remote servers.
• Sends Outstanding: If the 504 performance counter indicates that 504s are being received, then
this is a good counter to check. This value indicates the number of requests and responses that
are queued outbound: if this counter is high then the problem is probably not on this server.
This counter can also be high if there are network latency issues.

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Appendix A: How to Enable VMQ on Intel Network Adapter
Note: If you are using a network adapter teaming with the Intel network adapter, ensure that you
have Intel v15.0 (or higher driver available). Earlier versions do not support VMQ on a teamed
network adapter.
In a command prompt window, run the following to add the key to the host machine’s registry:
reg add HKEY_LOCAL_MACHINESYSTEMCurrentControlSetservicesVMSMP
ParametersBelowTenGigVmqEnabled /t REG_DWORD /d 1 /f

Then, enable VMQ on the driver:
1. In Control Panel, open the Device Manager and browse to Network Adapters.

2. Right-click the applicable network connection, click Properties, and then click the Advanced
tab.

3. In the Settings list, click Virtual Machine Queues, and then set the value to Enabled.

Figure 8 Advanced tab of Network Adaptor Properties, showing Virtual Machine Queue setting

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Appendix B: How to Increase Send/Receive Buffers on Intel Network
Adapter
1. In Control Panel, open Device Manager and browse to Network Adapters.
2. Right-click the applicable network connection, click Properties, and then click the Advanced
tab.
3. In the Property list, click Receive Buffers, and increase the value to at least 1024.
4. In the Property list, click Transmit Buffers, and increase the value to at least 1024.
5. Depeding on the driver version used, Receive and Transmit Buffers may not be visible here,
and rather “Performance Options” may be listed. If this is the case, open it and browse to the
settings for Transmit and Receive Buffers.
6. Click OK to save these settings.

Figure 9 Advanced tab of Network Adapter properties, showing Receive Buffers property.

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Appendix C: Changing the Bandwidth Limit for Application Sharing
You can change the upper bandwidth limit used by Application Sharing server by using the Set-
CsConferencingPolicy cmdlet in Lync Server Management Shell. 150 Mbps is the recommended
limit; after this point the virtual machines were observed to become CPU bound.
Run the following example cmdlet on the virtual Standard Edition server to change the Application
Sharing bandwidth:
Set-CsConferencingConfiguration -Identity global –
MaxBandwidthPerAppSharingServiceMb 150

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Appendix D: Performance Counters
In order to monitor performance in a virtual Lync Server site, the performance counters described in this
section should be observed. For details about how to create performance baselines, see the second part
of this section.

1 Lync Server 2010 Performance Counter Reference
For reference, the performance counter information in this section is separated by the Lync Server role
as follows:
• All Servers

• Front End Server

• Edge Server

• Back End Server

• Mediation Server

• A/V Conferencing Server

1.25 All Servers
Monitor the following performance on all virtual Lync Server system:
Performance Counter Details
Process(*)%Processor Time Monitor and collect (for Lync Server processes)
Process(*)%Privileged Time Monitor and collect (for Lync Server processes)

Process(*)%Private Bytes Monitor and collect (for Lync Server processes)

Process(*)%Virtual Bytes Monitor and collect (for Lync Server processes)

Processor% Processor Time (Total) It’s OK to see short CPU spikes at 70% or more – less than a few
minutes, but the CPU should normally operate at less than 70% during
peak load. If it is consistently higher, then determine if there are more
users connected than usual or if there has been some other change
that may result in higher load. Note this counter is representing the
virtualized CPU as the guest operating system sees it.

33


LS:SIP – 07 – Load Management; SIP – This should usually be less than 1 second on average but it’s normal to
000 – Average Holding Time For see short spikes of up to 3 seconds. The server will throttle new
Incoming Messages incoming messages after going above the high watermark and until the
number of messages falls below the low watermark. Check Outgoing
Queue Delay for delays sending messages to other servers or clients
LS:SIP – 01 – PeersSIP – 020 – Average
that could be causing messages to be accumulated in the server. The
server will drop client connections if it’s in a throttle state and
messages stay in the outgoing queue for more than 32 seconds.
The server starts rejecting new connections when average holding time
is greater than overload time of 15 seconds.
LS:USrv – 21 – Https Transport; USrv – Monitor and collect
002 – Number of failed connection
attempts / Sec

1.26 Front End Servers
Monitor the following Lync Server modalities on Front End Servers:
LC:AsMcu – 00 – AsMcu ConferencesASMCU – 010 – Connected Users Compare these
LC:AsMcu – 00 – AsMcu ConferencesASMCU – 010 – Active Conferences counters’ maximum
LC:ImMcu – 00 – ImMcu ConferencesIMMCU – 010 – Connected Users to the published
LC:ImMcu – 00 – ImMcu ConferencesIMMCU – 010 – Active Conferences
conferencing
numbers in this
LC:RGS – 01 – response group service call controlRGS – 009 – Current active calls
document.
LC:SIP – 01 – Peers(Clients)SIP – 000 – Connections Active
LC:DATAMCU – 00 – DataMCU ConferencesDATAMCU – 003 – Active Conferences
LC:USrv – 06 – Rich Presence Service SQL CallsISrv – 005 – Publications/Sec
LC:MediationServer – 00 – Outbound Calls(_Total)- 000 Current
LC:MediationServer – 01 – Inbound Calls(_Total)- 000 Current

Monitoring the individual processes on Front End Servers:
Processor(_Total)%ProcessorTime Monitor and collect
Processor(ASMCUSvc)%ProcessorTime
Processor(IMMCUSvc)%ProcessorTime
Processor(MediationServerSvc)%ProcessorTime
Processor(OcsAppServerHost#1)%ProcessorTime
Processor(RTCSrv)%ProcessorTime
Processor(RtcHost)%ProcessorTime

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Monitor following SIP/IMMCU/Database Store performance counters on all Enterprise Edition Front End
Servers:
LS:USrv – 01 - DB Store; USrv – 002 - Queue Latency Queue Latency: the time a request spends in the queue to
(msec) the Back End Server. The server will start dropping requests
when the database queue latency is >32 seconds.
Sporadic spikes of a few seconds are considered normal,
however the average latency should be < 100msec.
Server health decreases as latency increases to 32 seconds,
after which server throttling begins.
LS:USrv – 01 - DB Store; USrv – 004 - Sproc Latency Note: If for any reason (such as disk, memory, network, or
(msec) processor) on the Back End Server is too high, the queue latency
counter will be high. Queue latency can also be high if there is
too much network latency between the Front End Server and the
Back End Server.
If both Sproc Latency and Queue Latency counters are high, then
most likely the bottleneck is the SQL Server back-end database.
Check for disk IO contention first (see Physical Disk perf
counters).
SQL Database active transactions are a good indicator of which
database is having more contention than the others.
LS:USrv – 01 - DB Store; USrv – 020 – Throttled Rarely, requests are dropped from the queue due to
requests/sec database queue contention.
LS:Urv – 13 – Endpoint Cache;USrv – 001 – Active
Registered Endpoints
LS:SIP – 07 – Load Management;SIP – 000 – Average
Holding Time For Incoming Messages
LS:SIP – 07 – Load Management;SIP – 004 –Incoming
Messages Held Above High Watermark
Messages Held Above High Overload Watermark
Messages Timed out
MSSQL$RTCLOCAL: Buffer Manager - Page life The server could need more RAM if this counter is < 3600 which
expectancy indicates memory pressure by the system.
Additionally, there are few to no ‘reads’ on the database drive if
there’s enough memory, because SQL Server should only be
writing to the database.
LS:SIP - 07 - Load Management; SIP - 000 - Average
Holding Time For Incoming Messages
LS:SIP – 04 – Responses; SIP – 053 - Local 500 Indicates that there’s some server component that is not
Responses/sec functioning correctly.
LS:SIP – 04 – Responses; SIP - 055 - Local 503 The 503 code corresponds to server unavailable. There should
Responses/sec not be any 503s on a healthy server at a steady state. During
ramp up, after a server has just been brought back online, there
may be some 503s. However, as all users get back in and the
server returns to a stable state, there should no longer be any
503s.

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LS:SIP – 04 – Responses; SIP – 057 - Local 504 A few 504 responses to clients (for clients disconnecting
Responses/sec abruptly) is to be expected, but this counter mainly indicates
connectivity issues with other servers. It can indicate connection
failures or delays connecting to remote servers.
LS:SIP – 01 – Peers; SIP - 017 - Sends Outstanding (*) If there are 504 responses, this is a good counter to check. It
indicates the number of requests and responses that are queued
outbound, which means that if this counter is high then the
problem is probably not on this server.
This counter can be high if there are network latency issues
LS:ImMcu – 02 – MCU Health And Performance; The current health of the Instant Messaging “MCU”.
IMMCU – 005 – MCU Health State 0 = Normal
1 = Loaded
2 = Full
3 = Unavailable.
LS:USrv– 23 – Conference Focus Factory; USrv – 012 – Compare to total add conference requests to determine
Add Conference requests succeeded conference allocation failures.
LS:USrv– 24 – Conference Control; USrv – 018 – Local These counters indicate conferencing related failures.
C3P failure responses
LS:USrv– 26 – Conference Mcu Allocator; USrv – 009
– Factory Unreachable Failures
– Factory Calls Timed-Out
– Create Conference Mcu Unreachable Failures
– Create Conference Requests Timed-Out

Monitoring the following Performance Counters for the Web Servers component (applicable to Front
End Server and Director role)

LS:DATAMCU – 00 – DataMCU Conferences;
DATAMCU – 003 – Active Conferences ----
LS:DATAMCU – 00 – DataMCU Conferences;
DATAMCU – 025 – Number of Data MCU users in
any role --
LS:DATAMCU – 04 – MCU Health and Performance; The current health of the MCU. 0 = Normal. 1 = Loaded. 2 =
DATAMCU – 005 – MCU Health State Full. 3 = Unavailable.

LS:DATAMCU – 04 – MCU Health and Performance; The current draining status of the MCU. 0 = Not requesting
DATAMCU – 006 – MCU Draining State to drain. 1 = Requesting to drain. 2 = Draining.

Monitor the following performance For application sharing (ASMCU), observe the following:

36


LS:AsMCU – 02 – CCCP Processing ---- Monitor and collect
LS:AsMCU – 017 – CCCP Messages Retried/Sec ----
LS:AsMCU – 019 – Current CCCP Message Queue Size ----
LS:AsMCU – 029 – Number of add conference requests failed ----
LS:AsMCU – 030 – Number of add user requests failed ----
LS:AsMCU – 00 – AsMcu ConferencesASMCU – 000 – Active
Conferences
LS:AsMCU – 00 – AsMcu ConferencesASMCU – 003 – Connected Users

1.27 Edge Server
Monitor the following performance counters on Edge Server (Access Edge SIP component):
LC:SIP – 09 – Access EdgeSIP – 001 – External Messages/sec with Monitor and collect
Internally Supported Domain
LC:SIP – 09 – Access EdgeSIP – 003 – External Messages/sec
Received With Allowed Partner Server Domain
Received With IM Service Provider Domain
Received With a Configured Allowed Domain

Monitor the A/V Conferencing Edge component (audio/video and application sharing):
LS:A/V Edge – 00 UDP Counters:

LS:A/V Edge - 001 - Active Relay Sessions – Authenticated
LS:A/V Edge - 002 - Active Relay Sessions - Allocated Port
LS:A/V Edge - 003 - Active Relay Sessions – Data
LS:A/V Edge - 004 - Allocated Port Pool Count The value must be > 0. If it reaches 0 there
is a resource issue.
LS:A/V Edge - 005 - Allocated Port Pool Miss Count
LS:A/V Edge - 006 - Allocate Requests/sec
LS:A/V Edge - 009 - Allocate Requests Exceeding Port Limit If the value is > 0, this could indicate an
attempt to misuse the port.
LS:A/V Edge - 012 - Alternate Server Redirects
LS:A/V Edge – 019 – Session Idle Timeouts/sec
LS:A/V Edge - 021 - Packets Received/sec
LS:A/V Edge - 022 - Packets Sent/sec
LS:A/V Edge - 025 - Average Data Packet Latency (milliseconds)
LS:A/V Edge - 030 - Packets Dropped/sec This error occurs when an unexpectedly high
rate of User Datagram Protocol (UDP) packets is
received at the Media Relay (A/V Edge server)

37


causing some packets to be discarded. This
could be the result of system overload or an
indication of an attempt to misuse the MR.
To resolve this, check that the profile of
network traffic to the MR is in line with
expected usage. If the traffic exceeds 250
Mbps per interface then increase the
Receive and Transmit buffer size on the
associated network adapternetwork
adapters to three times the default values.
If the cause is a general system overload,
then increase capacity of the deployed MR
function. A network level trace can be used
to determine if there is an unusual amount
of traffic originating from a single source. If
the situation persists, then enable tracing
to check the network source of sessions
exceeding the bandwidth limits to allow
further troubleshooting of the cause.

LS: A/V Edge – 01 – TCP Counters:

LS:A/V Edge - 001 - Active Relay Sessions – Authenticated
LS:A/V Edge - 002 - Active Relay Sessions - Allocated Port
LS:A/V Edge - 003 - Active Relay Sessions – Data
LS:A/V Edge - 004 - Allocated Port Pool Count The value must be > 0. If it reaches 0 there is a
resource issue.
LS:A/V Edge - 005 - Allocated Port Pool Miss Count
LS:A/V Edge - 006 - Allocate Requests/sec
LS:A/V Edge - 009 - Allocate Requests Exceeding Port Limit If the value is > 0, this could indicate an
attempt to misuse the port.
LS:A/V Edge - 012 - Alternate Server Redirects
LS:A/V Edge – 019 – Session Idle Timeouts/sec
LS:A/V Edge - 021 - Packets Received/sec
LS:A/V Edge - 022 - Packets Sent/sec
LS:A/V Edge - 025 - Average Data Packet Latency (milliseconds)
LS:A/V Edge - 030 - Packets Dropped/sec This error occurs when an unexpectedly high
rate of TCP packets is received at the MR
causing some packets to be discarded. This
could be the result of system overload or an
indication of an attempt to misuse the MR.
To resolve this, check that the profile of
network traffic to the MR is in line with
expected usage. If the traffic exceeds 250
Mbps per interface then increase the
Receive and Transmit buffer size on the

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associate network adapter to three times
the default values.
If the cause is general system overload
then increase capacity of the deployed MR
function. A network level trace can be
used to determine if there is unusual
amount of traffic originating from a single
source. If the situation persists then
enable tracing to check the network
source of sessions exceeding the
bandwidth limits to allow further
troubleshooting of the cause.

Monitor the following on the HTTP relay (Web Server component with Reach client):
LS:WebRelay – 00 – Reach Web Relay Server* Monitor and collect

1.28 Back End Server
Memory (not applicable if guest VM has dynamic memory enabled)
% Committed Byes in Use Monitor and collect
Available Mbytes
Cached Bytes/[peak]
Network Interface:
Bytes Total/sec <All instances> Monitor and collect
Physical Disk:
% Idle Time (*) A consistently small percentage of idle time is usually an
indication of poor disk performance.
Ave. Disk Queue Length (*) Disk Queue Length per drive should be no more than double the
number of spindles backing up that drive.
Avg. Disk Sec/Read(*) Any average numbers above 1.5 msec usually indicate poor disk
Avg. Disk Sec/Write(*) performance.
Process:
Process(*)%Processor Time Monitor and collect
Process(*)%Privileged Time
Process(*)%Private Bytes
Process(*)%Virtual Bytes
Processor Information: Short CPU spikes of around 80% or more for less than a few
% Interrupt Time (_Total) minutes is to be expected, but the CPU should normally operate

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% Processor Time (_Total) at less than 80% during peak load. If it is consistently higher, then
determine if there are more users connected than usual or if
there has been some other change that may result in higher load.
Database:
SQLServer:User SettableUser Counter 1 Approximate number of active endpoints in the pool.
MSSQL$RTC:Databases(rtc)Active A high number of active transactions usually indicates database
Transactions transaction contention.
MSSQL$RTC:Databases(rtcdyn)Active Monitor and collect
Transactions
MSSQL$RTC:Databases(tempdb)Active
Transactions

1.29 Mediation Server
The following performance counters should be used to measure the performance of the Mediation
Server:
LS:MediationServer - 00 - Outbound Calls- The total number of active calls going through the Mediation
000 – Current Server.
LS:MediationServer - 00 - Outbound Calls- Total number of active calls going through Mediation Server that
006 – Active media bypass calls are in Media Bypass mode. Calls using Media Bypass use
significantly fewer Mediation Server resources because the media
is not flowing through Mediation Server.
LS:MediationServer – 04 – Global Total number of active channels that are having Phase Shift
Counters-000 Current Audio channels with Modulation (PSM)quality reported. Calculating PSM quality has a
PSM quality reporting processing overhead so this should be taken into account when
measuring performance.
LS:MediationServer - 01 - Inbound Calls- 000 Monitor and collect
– Current
LS:MediationServer - 00 - Inbound Calls- 006
– Active media bypass calls

40


The following performance counters can be useful when troubleshooting the Mediation Server
component:
LS:MediationServer - 02 - Media Relay- 001 - The number of calls where media connectivity between
Media Connectivity Check Failure Mediation Server and the remote endpoints could not be
established.
LS:MediationServer - 03 - Health Indices- 000 Scaled index between zero and 100 that is related to all call
- Load Call Failure Index failures due to Global Health Index as heavy load.
CS:MediationServer - 04 - Global Counters- The number of calls that failed because of an unexpected
001 - Total failed calls caused by unexpected response from the Front End Server.
interaction from the Proxy ----

CS:MediationServer - 05 - Global Per Gateway The number of calls that failed because of an unexpected
Counters- 000 - Total failed calls caused by response from a gateway peer.
unexpected interaction from a gateway

1.30 Audio/Video Conferencing Server
Monitor the following Performance Counter with applicable threshold levels (implement in System
Center Operations Manager Lync Server Management)

LS:MEDIA - 01 – PlanningMEDIA - 009 - Number of occasions Error Threshold = 30
conference processing is delayed significantly AVMCUSvc.exe Experiencing transient audio quality
issues due to CPU load

LS:SipEps - 02 - SipEps ConnectionsSipEps - 010 – Error Threshold = 1 (in 4 consecutive)
NumberOfDNSResolutionFailures*avmcusvc*

The events in the Lync Server event log reflect media stack health:
Event ID Details
32013 Audio Video Conferencing Server health monitoring has If the A/V Conferencing Server reaches these
detected that Audio Video Conferencing Server is running at a points then subsequent operations to add
moderate capacity (Warning or Error) new conferences and new users will be
rejected until the health returns to normal
state.

1.31 Establishing Performance Baselines
In order to establish a performance baseline, use the following counters

1.31.1 Resource Utilization Baseline Tests
Processor; % Processor Time (_Total)
Process; % Processor Time (RtcSrv)
Process; % Processor Time (IMMcuSvc)
Memory; Pages/sec ---
Network Interface; Bytes Total/sec ([your network adapter])

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1.31.2 User Load Baseline Tests
LS:SIP – 01 - Peers; SIP - 028 - Incoming Requests/sec (_Total)
LS:SIP - 01 – Peers; SIP – 001 – TLS Connections Active (_Total)
LS:SIP – 01 – Peers; SIP – 000 – Connections Active (_Total)
LS:SIP – 02 – Protocol; SIP - 001 - Incoming Messages/sec ----
LS:ImMcu – 00 - IMMcuSvc Conferences; IMMCU – 000 - Active Conferences ----
LS:ImMcu – 00 - IMMcuSvc Conferences; IMMCU – 001 – Connected Users ----
LS:USrv – 00 – DBStore; Usrv – 002 – Queue Latency (msec)
LS:USrv – 00 – DBStore; Usrv – 004 – Sproc Latency (msec)

1.31.3 Multipoint Conferencing Unit (MCU) Resource Utilization Baseline Tests: (Monitor on
All MCUs)
Processor; % Processor Time (_Total)
Network Interface; Bytes Total/sec ([your network adapter])
Memory; Pages/sec (---)
Process; % Processor Time (ASMCUSvc)
Process; % Processor Time (AVMCUSvc)
Process; % Processor Time (DataMCUSvc)
Process; % Processor Time (MeetingMCUSvc)
Process; Private Bytes (ASMCUSvc) ([peak])
Process; Private Bytes (AVMCUSvc) ([peak])
Process; Private Bytes (DataMCUSvc) ([peak])
Process; Private Bytes (MeetingMCUSvc) ([peak])

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Server virtualization Lync Server 2010

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