This post is authored by Akshai Parthasarathy, Baaskar R, and Andrew Coleman from Global Solutions Engineering

In April of this year, the Global Solutions Engineering team delivered a Lync Server 2010 Virtualization Whitepaper and an accompanying Reference Architecture booklet. We also went into more detail through blogs, showing the virtual host configuration for Lync Server 2010 that we used, and presented how we scaled out and measured Lync performance when testing our architecture. Based on feedback, we have enhanced these deliverables with additional Back End SQL database results and more information about the Edge Servers.

The data generated for both of these deliverables was obtained by using the Lync Server 2010 Stress & Performance Tool and the sizing guidance provided in the Server Virtualization in Lync Server 2010 whitepaper.

Updated Whitepaper with SQL Database Results

The whitepaper that centered on the sizing of Lync Server is now updated with Back End SQL database sizing information. This paper now recommends where to place the SQL database and log files, and it also recommends LUN sizes, number of CPU, memory size, and disk latency for the SQL components. We conducted tests by varying the number of user logins per minute from 100 to 200 to 400 users per minute. This represents the peak number of users that login to Lync. For instance, our test methodology represents the real world scenario when 100, 200, or 400 Lync users login to the client between 8 and 9 o’clock in the morning.  Our data indicates that with a single PS6100XV Equallogic storage array (24 x 146GB 15k disks), disk latencies are sufficiently low for minimal impact to Lync performance, even for the maximum  user login rate of 400 users/minute. This login rate corresponds to conditions that may be experienced in a fairly large Lync deployment of about 25,000 users, assuming a login period of one hour (8am – 9 am). Shown below is a figure from the whitepaper for these Back End SQL disks and their latencies.

As shown above, the disk performance on a single Equallogic array with 15k spindles is adequate for this login rate. Based on this data, the whitepaper also recommends a sample reference configuration for 12,000 Lync users which now includes a validated Back End component and a recommendation for Edge Servers in the perimeter network.

Updated Reference Architecture Booklet

We at the Global Solutions Engineering team have also updated the Lync Reference Architecture booklet to include the latest PowerEdge servers, Equallogic storage, and PowerConnect and Force10 switches. This booklet provides a design overview of the server, storage and networking required for deployments starting at 500 and scaling up to 25000 users. Edge Servers are now included in these designs and the back-end is sized based on our findings in the lab.  This updated RA booklet can be found here.

We hope you find these papers useful. We look forward to any comments on this blog post!