A Sizing Study of Microsoft® Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Make the most of Dell hardware running Microsoft Lync Server Global Solutions Engineering Dell
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers This document is for informational purposes only and may contain typographical errors and technical inaccuracies. The content is provided as is, without express or implied warranties of any kind. © 2012 Dell Inc. All rights reserved. Dell and its affiliates cannot be responsible for errors or omissions in typography or photography. Dell, the Dell logo, EqualLogic, and PowerEdge are trademarks of Dell Inc.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Contents Executive Summary .................................................................................................... 5 Introduction, Scope, and Purpose ................................................................................... 6 Advantages of Dell with Lync Server ................................................................................ 6 Overview of Lync Server .........................
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Tables Table 1. Configuration of R720 (Lync VMs host) ............................................................... 14 Table 2. Configuration of R610 (Back-End Server) ............................................................ 15 Table 3. LUNs for SQL and Capacity Requirements ........................................................... 15 Table 4. Log Files in LUN 5. ....................................
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Executive Summary Microsoft Lync Server provides enterprise-grade communications for instant messaging, Web/audio/video conferencing, application sharing, and telephony (or voice over IP). Users within an organization use the Lync client to connect to a Lync Server, and then use it to communicate with other users.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Introduction, Scope, and Purpose This paper begins with an overview of the Lync Server workload and the advantages of using Dell’s latest R720 server, and then details the test environment and analyzes the collected performance metrics. Finally, based on the study’s results, the paper presents a reference configuration for the Lync Server 2010 on PowerEdge R720 using virtualization.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Figure 1. Dell PowerEdge R720 For the Back End SQL Servers, the R620 is again a good choice. For the purposes of this paper, the R610 was used to generate performance data. However, with a similarly equipped 6-Core Intel Xeon on Dell’s 12th generation servers, performance should be at par or better than the older R610. Figure 2.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers two Dell Force10 S-Series 1Gbps top-of-rack switches are used – the Dell Force10 S55 and the Dell Force10 S60. Both these switches provide 1U top-of-rack 1/10 GbE connectivity, which is sufficient for the reference configuration. The S60 access switch provides deeper 1.25Gb buffer and is recommended for iSCSI SAN using Equallogic PS Series arrays in a redundant configuration.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Overview of Lync Server Microsoft Lync Server 2010 Enterprise Edition is a communications server solution that supports enterprise-level collaboration requirements. The Enterprise edition was selected for this study because it provides improved scalability and high availability.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Figure 5. Lync Server Topology Builder Central Management Store and Active Directory Lync uses a new Central Management Store (CMS) that stores server and service configuration data. Individual user information, such as the user policy, the user’s SIP URI, and the user’s phone number, are stored in the CMS database. The CMS also provides data to the Lync Server Management Shell and file sharing.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Figure 6. Lync Server Control Panel Lync Server Roles To test the scalability of Lync in a virtual environment, the Front End, A/V Conferencing, Mediation, Monitoring, and Back End server roles were installed. The Front End, A/V, and Mediation Server roles were collocated in the lab deployment and these roles are described in the sections below.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Mediation Server (collocated with Front End) This server role bridges Public Switched Telephone Network (PSTN) traffic to and from the media gateway to the Lync server network. It supports the routing of outbound calls to multiple media gateways, instead of a single media gateway as was the case in Office Communications Server.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Monitoring Server A monitoring server role can be deployed to collect statistical usage metrics for IM, conferencing, and Enterprise voice by tracking call detail records. It uses a back-end SQL database to store usage metrics through the SQL reporting services.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Connections from 7 am – 9 am: 6400 Login Rate = 6400 / (2 * 60) = ~50 users/min PowerEdge System Configuration This study configured the PowerEdge server using Microsoft and Dell best practices, taking into consideration Lync and hypervisor requirements. For the test, a PowerEdge R720 running Windows Server 2008 R2 with Service Pack 1 and the Hyper-V role was utilized.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Table 2. Configuration of R6102 (Back-End Server) Server CPU Memory Operating System SQL Storage Disks Dell PowerEdge R610 2 x Intel Xeon X5550 (8 cores @ 2.67 GHz) 48 GB Windows Server 2008 R2 SP1 Microsoft SQL Server 2008 R2 Equallogic PS6100XV 24 x 2.5‖ 900GB 10k SAS3 For the logical disks, 6 LUNs were created.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Cpsdyn Rgsconfig Rgsdyn Logs for Call Park Service Logs for Response Group Service (configuration Information) Logs for Response Group Service (runtime operations) The final volume contains all the data files for those logs placed in LUNs 1,2,4, and 5. The contents of this LUN are: Rtcdyn.mdf Rtc.mdf Rtcab.mdf Rtcab1.mdf Cpsdyn.mdf Rgsconfig.mdf Rgsdyn.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers As shown above, volumes 1, 2, 5, and 6 should be made accessible from the SQL Back End. Volumes 3 and 4 should be accessible from the Archiving/Monitoring Server. The SQL servers will have dedicated NICs connected to the iSCSI SAN, which is also attached to the Dell Equallogic storage array.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Performance Counters from Front End Server VMs and Hyper-V Host To collect more fine-grained data, performance counters were captured while running the Stress and Performance tool; these counters were collected on the Front-End and Host Hyper-V servers. Some of the important performance counters and thresholds used for the analysis are below. Table 6.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Initially, the tests were executed on a single Hyper-V virtual machine to establish the number of users that can be supported while maintaining performance thresholds. It was found that the Front End VMs running on the R720 could support 3000 users using the heavy profile for all the supported end-user features in the Stress and Performance tool.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers fixed time period. For this study, a time period of 8 hours was selected for analysis, and the QoE indicators measured are in the following table. Table 7. Monitoring Server QoE Statistics and Thresholds QoE Metric Jitter Packet Loss MOS Round Trip Time Threshold < 20ms < 0.1% < 0.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers instances when the SQL Server has to fetch a page from disk after it was not found in its memory. The page faults/sec counter measures the soft page faults in addition to the hard page faults. These soft page faults happen when pages are found at other locations within main memory and these are not as expensive as retrieving pages from disk.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Total Number of Data Conferences Active Distribution List Calls per second CAA Calls in progress Results and Analysis Three test scenarios were run, and the results were collected from the Front-End VMs, Host, Monitoring Server Reports and the Stress and Performance Tool counters. The three major scenarios in the testing included: Table 10.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers to be within acceptable levels, the counters from the Stress and Performance Tool are also verified to be within acceptable levels, and then the discussion of the SQL Server Back End performance continues.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Figure 9. Conference Distribution per Front-End for 12,000 users Front End A 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% Front End B Front End C Front End D 25.73% 25.42% 25.82% 25.28% 24.73% 24.91% 24.55% 25.20% 25.82% 25.10% 25.88% 23.77% 23.72% 24.58% 23.75% 25.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Figure 10. Processor Utilization and Scaling as Lync Users Increase Processor Utilization 70% 60% 50% 40% VM Processes 30% Hypervisor Processes 20% Total Processes Threshold 10% 0% 1 2 3 4 Number of VMs In the chart above, there is a linear scaling of CPU usage when the user load is increased from 3000 users on one VM to 6000 users on two VMs, and then to 12,000 users on four VMs.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Again, the available memory shows a linear relationship to the number of users supported by the VM’s. As the number of users ( & VM’s) increases on same HyperV host, the available memory decreases; however, the decrease is not close to the prior set threshold of 15%. At 12,000 users, the teamed NIC proved to be sufficient.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Table 14. QoE Summary for Conferencing QoE Metric Threshold Jitter Packet Loss MOS Round Trip Time < 20ms < 0.1% < 0.5 < 200ms 3000 users 1ms 0 0.07 1ms 6000 users 1ms 0 0.08 1ms 12,000 users 1ms 0 0.08 1ms As shown above, both peer-to-peer and conference scenario statistics are within acceptable QoE limits.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers within the thresholds. The average memory utilized was around 5 GB of the required 32 GB and the memory fluctuation shows no trend. For CPU, the trend is almost linear, and assuming that this behavior continues, the estimated number of user logins per minute supported would be approximately 4000 users/min.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers The remaining memory counters also looked healthy and these are shown in the table below. Table 16. Back End SQL Memory Counters Memory Counters Threshold Page Faults/sec Pages/sec Page life expectancy < 2500 < 1000 > 3600 100 users/min 200 users/min 400 users/min 228.36 0.24 4660 448.99 0.22 3686 301.33 0.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers As seen above, the latencies on the data volume (LUN 6) are higher than the others, but well within the acceptable limit of 20ms. The corresponding counters for disk transfers/sec, which measure the IO activity on the storage subsystem housing these volumes is summarized in the table below. Table 17. Disk Transfers/sec vs User Login Rates LUN 100 users/min 200 users/min 400 users/min RTC Log RTCDYN Log 34.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Table 19.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Figure 14. Reference Architecture for 10,000 users on Dell PowerEdge Servers The storage and networking are enabled by Dell EqualLogic PS6100 series arrays, with 15k SAS drives and Dell Force10 S60/S55 switches respectively. Note that the deployment does not include the Archiving/Monitoring role or the Director pool as these are not part of the sizing study.
A Sizing Study of Lync® Server 2010 and its Back End SQL Database on Dell™ PowerEdge™ Servers Conclusion This paper presented testing results from a virtualized Microsoft Lync Server 2010 deployment on a Dell PowerEdge R720 server. It discussed the new capabilities on the PowerEdge servers, and how the Lync Server scales well with these new hardware features. By collecting data from the Lync Stress and Performance Tool and performance counters, the almost linear scaling of Lync Server 2010 was observed.
