I’m very excited to announce the release of a new Cisco Validated Design (CVD) that documents a reference architecture and the scalability tests we completed over the past few months.  This architecture integrates Citrix XenDesktop and XenServer with the Cisco Unified Computing System (UCS) and NetApp storage to build an enterprise-ready virtualization solution. 

During our test, the design showed excellent performance and scalability with a combined 2,000 seats of mixed FlexCast models — both hosted virtual desktops and hosted shared desktops.  We limited our testing to 2,000 sessions, but the architecture is well suited for deployments of all sizes, including large departmental and enterprise deployments, and can easily grow based on future needs. 

This blog post will give you highlights about our test; you can read the full details in the CVD.

Citrix XenDesktop 7 transforms the delivery of Microsoft Windows apps and desktops into a secure, centrally managed service that users can access on any device, anywhere. XenDesktop 7 allows users to search for and subscribe to published resources, enabling a service delivery model that is cloud-ready.

This CVD leverages Citrix XenDesktop and XenServer on top of predefined, validated infrastructure packages from Cisco and NetApp, known collectively as FlexPod.

Building a Scalable Architecture

This enterprise solution combines the following components: Citrix XenDesktop 7.1, XenServer 6.2 SP1, Cisco UCS B200M3 blades with Intel Xeon E5-2680 (Ivy Bridge processors) and NetApp FAS 3250 shared storage running the Clustered ONTAP 8.2 storage operating system.  For high availability, the architecture uses an N+1 server design that features two Cisco UCS chassis housing two blades for the infrastructure server pool, eight blades for the virtual hosted desktop pool and four blades for the hosted shared desktop pool, as shown in the diagram below:

The CVD documents a design that was stress-tested and validated by the Citrix Solutions Lab with 550 hosted virtual desktops (Windows 7) and 1,450 hosted virtual desktop sessions (Windows Server 2012). 

During this project, we incorporated test phases that allowed us to intelligently scale up to the targeted 2,000 sessions as follows: Determining single-server scalability limits, validating single-server recommended load, validating single pool for each FlexCast model, and ultimately validating the full scale with multiple combined pools.  We have followed Cisco’s testing protocol for all test phases. 

We have compiled the test data and results for all phases in the CVD.

The following shows the Login VSI chart for the full-scale test (2,000 sessions):


What‘s the outcome?

The combination of technologies from Citrix, Cisco and NetApp produced a highly efficient, robust and affordable desktop virtualization solution for a mix of hosted virtual desktops and hosted shared desktops supporting different workloads.  The configuration, as tested, easily supported the 2,000-session full-scale mixed workload without overwhelming CPU, memory, networking or storage subsystems.  More importantly, this architecture is enterprise-ready with a built-in high-availability design that provides N+1 server fault tolerance for hosted virtual desktops, hosted shared desktops and infrastructure services.  The new-generation Ivy Bridge processor provides higher density than older generation processors, thus supporting greater capacity under the same footprint.  This entire configuration was positioned in a single 42U rack that was not fully utilized.