This document outlines the process for defining hardware requirements for Microsoft Lync Server 2013 through stress testing and capacity planning. It emphasizes the importance of understanding user scenarios and the technical specifications needed for optimal performance. Additionally, it provides guidelines for conducting stress tests and validating server performance to ensure a successful deployment.

1. Lync Stress Test - Key Health Indicators KHI (how to design/
define the server hardware requirements)
© 08.06.2014, Thomas Pött, Microsoft MVP Lync and PLSL 3rd level
Support certified.
Version 1.0
Introduction............................................................................................................................................. 2
The Calculation Process (I recommend to you): ..................................................................................... 4
The Stress Test Process: .......................................................................................................................... 5
The Validation Process: ........................................................................................................................... 6
The technical level of this document is 300.
This article requires knowledge about Microsoft Performance Monitor, Lync Monitoring, Hardware SPEC’s and
Consulting.
Building the Test User Scenario, requires full understand of each Lync feature and how user will utilize those
feature. Please also carefully understand the Lync PSTN Gateway Simulator. The Simulator must be provide
with correct Dial-Plans, Voice Policy and Voice Routes.
You also need to understand the Lync User Provisioning Tool and how to design the Stress Test Scenarios.
The
Note:
This document is neither a sizing nor a configuration guide. You should use this document only for your
environment planning’s purposes and security considerations. In lager environments you should spend some
time to evaluate the optimal path of your Lync deployment.

2. Introduction
Since Microsoft released Lync Server 2013, there was one change in the planning
document. No detailed SPECs were released so you could exactly calculate your
server performance requirements.
Truly, there is the performance calculation sheet which provides you with a rough
overview.
For this entire process you need the following tools and documents:
 Lync Server 2013 Capacity Calculator
 Lync Server 2013 Stress Testing Guide
 Lync Server 2013 Stress and Performance Tool
 Key Health Indicators: The Foundation for Maintaining Healthy Lync Servers
 Planning a Lync Server 2013 Deployment on Virtual Servers
 Lync Call Quality Methodology poster
I provide you with the Lync KHI Performance Counter: Download here
Note:
The XML I have provide contains a consolidated Lync Frontend installation entirely
on drive C: with 6 CPU core. If you have another setup, please add more CPU
counter and if the SQL Server is installed on drive D:, please also add the I/O
counters for this drive too.
But generally the server hardware requirements are physically and virtually the same:
Front End, Back End, Standard Edition, pChat - Server
Component Minimum requirements
CPU 2x64 bit CPU with 6 Core (also if virtualized)
Memory 32 GB
Disk 2x RAID 1 min. 72GB1[1] free space
6x RAID 10 for SQL databases
Network 1x Dual-Port network card with min. 1GBit/Sec
If teaming is activated, unique MAC address must be used
1[1] It is required having at least 20GB free disk space after installation, else it might have a
serious impact during update and CU installations, this is related to the local SQL database
copies.

3. Edge, Standalone Mediation – Server and Director, Office Web Apps
Component Minimum requirements
CPU 64 bit CPU and min. 4 Core (also if virtualized)
Memory 16 GB
Disk Mind. RAID 6 Performance with min. 72GB free space
Network 1x Dual-Port network card with min. 1GBit/Sec
If teaming is activated, unique MAC address must be used
This general definition for your hardware is simply not enough if you design your
environment. There are some questions you need to answer to your customers:
- how can I guarantee the hardware performance on virtual environments
- how does Lync impact our SAN
- if we don't utilize the max user, how and can I reduce CPU's and RAM, or even the
SQL Disk I/O's
Here you stand as consultant and don't know what to say.
E.g. the supportability matrix give you a clear answer, design the server as provided
in the requirement document.
So, say you have 3 Frontend servers as recommended for High Availability (HA), but
you only run 1.000 users.
This would be a complicated answers, since you simply cannot know the answer, as
it was possible with Lync 2010, since you had more information how to calculate.

4. The Calculation Process (I recommend to you):
Lync server load highly depends on the user profile!
Talk to your customer and figure out what is the main purpose and how in the past
users utilized Voice (PSTN and PBX)
Analyze the Video utilization, also and especially the AppSharing (with is video data
too)
Start using the Lync Server 2013 Capacity Calculator.
With the results popping up you need to reverse engineer the capacity needed on
your servers.
Finally you have some SPEC's, but you need (better say: MUST) validate them if you
are not using the exact SPEC provided in the tables above.

5. The Stress Test Process:
Please use the Stress Test Guide from Microsoft and setup the environment in a Test
Lab first. It simple even on physical, as well as on virtual environment.
Some recommendations from my experiences:
1. the Stress Client SPEC's are not sufficient as Microsoft wrote, please use here
more CPU's, at least the double amount.
2. Split the Test across 3 Stress Clients,
Stress Test Client 1: All IM, APPClients and Conferences
Stress Test Client 2: all Reach Client features
Stress Test Client 3: all PSTN functions (PSTN Gateway Simulator), here you
might need more clients, since the PSTN Simulator can only provide one (1) gateway
on a PC
3. run a Pre-Test, where you closely monitor you client performances, especially the
CPU after the so call RAMP UP TIME
4. Check if information are written to the Lync Monitoring Database (validate the
reports)
5. Re-balance some of you Test Scenarios and run the Step 3 again if necessary
6. Start the Main Stress Test now
Now it's time for the core test itself.
Ensure you either monitor the KHI on a dedicated machine or on the Lync server
themselves. Please do NOT use any of the Stress Test Clients! I have provided you
with the Performance Monitor DataCollection. Make sure you see some results
during Step 3.

6. The Validation Process:
Now you have all results necessary to write your report and even see you
underestimated the server load ;)
Get the Performance Data and see if any of the counters above did jump above
some of the provided counters for a longer periods of time or if any of those counters
jump more frequently above the thresholds.
The go to the Lync Monitoring Reporting and validate all Failure Reports (related to
the test you have ran).
I also recommend checking the Lync Server Eventlogs.
With the collection and analysis of all data write your own validation paper to the
customer.
NOTE:
If you need help, don't hesitate asking me for help, I can provide you professional
service and do the write-up for you.
Use the contact app on the right side of my blog.
Author: Thomas Poett MVP, Managing Consultant Microsoft Unified Communication