Cisco has released a paper titled: Reference Architecture Based Design for Implementation of Citrix XenDesktop Using Cisco Unified Computing System, Microsoft Hyper-V, and NetApp Storage. The paper is really exhaustive and contains 162 pages. This paper reports the results of a study evaluating the scalability of the Citrix XenDesktop environment on a Cisco Unified Computing System (UCS) B-Series Blade Servers running Microsoft Hyper-V connected to a NetApp Storage array.
In order to test the configuration the best practice recommendations and sizing guidelines for large-scale customer deployments of Citrix XenDesktop on the Cisco Unified Computing System were applied. LoginVSI version 2.1 was used to determine the maximum amount of desktops that could be loaded on a single server with an acceptable user response time.
Outcome of the design validation:
- The Citrix XenDesktop Hosted VDI FlexCast delivery model running on Microsoft Hyper-V platform with Cisco UCS B250-M2 Blade Servers was successfully validated.
- Scale testing findings: 110 Windows 7 (64 bit) 1.5 GB desktops running knowledge worker load on a single B250-M2 blade server with 192 GB of memory.
- Memory Extends Density: With 192GB of RAM, the B250 M2 blades offers an optimal memory configuration for desktop virtualization that allow the hosting infrastructure the ability to fully utilize the CPU capabilities of the servers without restricting the of amount memory allocated to the desktops. With the large memory blade we are seeing the best performance for the price.
- Linear scalability when we went from 1 server to 8 servers to 16 servers: the results showed that with 1 server we had 110 desktops and with 16 we got 1760 desktop with the same response time.
- Pure Virtualization: The validated environment consisted of only virtual machines hosted on Microsoft Hyper-V. All the virtual desktop and supporting infrastructure components including Active Directory, Citrix Provisioning Server, and the XenDesktop Desktop Delivery Controllers were hosted on Microsoft Hyper-V. This is a clear testimony of the robustness, reliability and availability of the Microsoft Hyper-V virtualization platform in use, as we no longer needed to dedicate physical servers for PVS, DDC, and other services.
- Rapid provisioning with Cisco UCS Manager makes it easy for scaling from 1 chassis to 2 and so on.
- The 10G unified fabric story gets a stronger validation as we see tremendous performance with respect to user response times during the load test.
- The low latency Cisco Virtual Interface (VIC) cards makes the configuration more robust in terms of extra vNICs and contributes positively towards the response time equation.
- With proper backend storage scaling we can scale out UCS domain from 4 chassis and beyond without making any changes to the proposed Reference Architecture.
- Storage Simplicity for Desktop Virtualization: NetApp’s ability to aggregate multiple storage volumes greatly simplifies the storage needs for desktop virtualization.
- Desktop virtual machine Boot-ups or Logon Storms (from rapid concurrent or simultaneous user log-on’s) have the largest scalability impact to this solution as well as to VDI environments in general.