Extreme Density:  5,768 Hosted Shared Desktops in a single Blade Chassis

With IBM® Flex System™ x222 Compute Node and Citrix XenDesktop 7™

In August we looked at a new Server Platform from IBM called the FlexSystem x222 Compute Node, as well as a tremendous amount of interesting and innovative solution testing that IBM labs in Austin undertook with XenDesktop 5.6 and published on the IBM Smart Cloud Desktop Infrastructure solution page.

In that testing IBM showcased the ability to host 4256 VDI medium users within a single blade chassis.  They also provided detailed and comprehensive scalability guidance around processors, memory, storage and networking.

Today, I am very excited to announce that the IBM Austin lab has updated their guidance and numbers for XenDesktop 7.  And what is better, they added new user scenarios within their solution testing, including scalability guidance for Hosted Shared Desktops.

The reference architecture document is available here: IBM SmartCloud Desktop Infrastructure with Citrix XenDesktop.  And this document includes the newly announced IBM PureFlex Solution for SmartCloud Desktop Infrastructure – a pre-configured, integrated VDI offering optimized for VDI deployments and available with both the Intel processor-based IBM Flex System™ x222 and Flex System x240 compute nodes.

Before we get to the numbers, let me quickly remind you what the IBM FlexSystem x222 is and what makes is so unique in the industry.

“The Flex System x222 Compute Node is optimized for desktop virtualization and was created to meet the demand for more compute capability within an existing physical footprint. The density of a standard IBM Flex System node is doubled, providing two twin nodes per standard compute bay in the IBM Flex System Enterprise Chassis for the equivalent of up to 28 nodes per chassis. The Flex System x222 uses two Intel Xeon processors and up to 384 GB of memory per twin compute node and can support up to twice the number of processors compared to the traditional approach in the same rack space.”

As highlighted in my previous blog, and documented by IBM in the Citrix XenDesktop reference architecture, a single IBM x222 blade can support 152 concurrent VDI users, all simultaneously running VSI Medium Task worker when running XenDesktop 5.6 while providing a solid user experience.

That equates to 4256 Medium Task workers supported within a single blade chassis. 

That kind of density equates to a lot of potential savings to our customers in both infrastructure costs (less stuff to buy), space (less datacenter footprint), heat/cooling/electricity (save money and help the environment), and even complexity of setup and build out.

It truly is an astonishing number, and showcases a lot of power packed in a small foot print.

However with the XenDesktop 7 and using the Hosted Shared Desktops configuration… the density results IBM is reporting this time… are simply astounding.

As shown in the table below (borrowed from page 13 of the IBM document).  Using 2xE5-2470 2.3 GHz processors, IBM was able to support 206 users on one of the twin servers within an IBM x222 blade.  (Note:  That is running exactly the same Medium Task simulated workload as described above.)



# of VMs

Maximum   Users


Windows Server 2008 R2




Windows Server 2008 R2




Windows Server 2008 R2



So… let’s work this math out…

206 workers on 1/2 of the x222 blade = 412 users on a full x222 blade!

And as you can fit 14x Blades in a chassis…

That is 5,768Medium task workers

All happily reading e-mail, surfing the web, watching videos and building presentations … and all serviced from within a single blade chassis. 

(Again this number does not include the necessary reductions for disaster recovery planning, so your millage will vary. But the IBM document provides solid guidance for calculating and planning for your DA requirements.)

Additionally, in showcasing various scalability configurations and their results, IBM has also provided our customers with the ability to choose the configuration that is best for you.  For various reasons, including licensing of the Windows Virtual machines, some of you may opt for a 4x VM configuration, instead of 8x VM configuration.  And thanks to the information and detail provided, you can make that decisions based on real world numbers and tradeoffs.

There is so much more detail, guidance, and testing provided within the IBM paper and as well as capabilities in the solutions they describe.  This blog simply highlighted one of the many reasons you need to spend some time investigating these solutions for yourself.

IBM SmartCloud Desktop Infrastructure with Citrix XenDesktop

IBM Smart Cloud Desktop Infrastructure.

IBM Pure FlexSolution for SmartCloud Desktop Infrastructure

My previous blog on the subject can be found here.  Density Reimagined with IBM® Flex System™ x222 and Citrix XenDesktop™