Is it worth deploying VDI ?

Over the last couple of days I have configured a POC deployment of XenDesktop over VMWare. Apart from a small stumbling block to do with SSL certificates on the host server it was simple enough to deploy a LAN based XenDesktop environment. Configuring a web based deployment was slightly more challenging but that was more down to my limited test environment in my cupboard/office than anything else.

In the next couple of weeks I hopefully will have time to build a similar text environment with VMWare View. I will compare the two products after tests are complete.

Getting back to the topic in hand, I was debating if there is a good ROI and lower TCO argument in deploying a VDI solution over a TS or physical environment

I have deployed Citrix Metaframe/Presentation Server/Xenapp6/Terminal Services and for the majority of users fail to see why they need anything but the standard set of corporate applications be it the defacto MS Office, the corporate version of CRM or finance system.  You can have a much higher user density with TS than you can with VDI.  Higher Density means fewer server’s and lower cost of infrastructure.

TS & VDI are both a style of Server Based Computing (SBC) and therefore have some of the same limitations such as remote display protocols.  They both provide a much lower TCO over thick provisioning.

So we are only talking about the smaller percentage off users that need to run applications that will not run in a shared server user environment such as TS but will run is a shared server VDI environment.

There are advantages with VDI over TS:-

• High Availability – Live migration of individual VDI’s
• The ability suspend your machine and reduce the load on the Host
• Better Load Balancing
• Improved software licensing control

As technology marches on the user density gap will narrow between TS and VDI and with it the cost differential will reduce.

For now the first question to ask is “Do my applications require a VDI solution”

Forgetting about the potential reduced ongoing management costs lets compare physical desktops to virtual as equipment only costing model.  We will assume that an infrastructure already exists for Active Directory, VCentre and storage.

Physical deployment

• Cost of  deploying a physical machine excluding desktop applications = £500
• ———————————————–
• Department of 10 people = £5000
• Department of 30 people = £15,000
• Department of 50 people = £25,000

Virtual deployment

• New ESX server of sufficient spec to support 50 Virtual Windows 7 Machines = £10,000
• 4 ESX Processor Licenses = £8000
• W2k8R2 server license for Xendesktop studio = £500
• 1 Licenses for Windows 7 = £90
• 1 License for XenDesktop (Enterprise) = £150
• ————————————————-
• Department of 30 people = £25,700
• Department of 50 people = £30,500

In the Virtual Deployment costs you will notice that this does not include the costs of terminals to run the VD’s on.

• 30 terminals = £7,500 + £25,700 = £33k
• 50 terminals = £12,500 + £30,500 = £43k

Xenapp 6 deployment

As a comparison below is the same spec server running Xenapp6:-

• New ESX server of sufficient spec to support 50 Virtual Windows 7 Machines = £5,000
• 2 ESX Processor Licenses = £4000
• W2k8R2 server license = £500
• 1 TS CAL = £50
• 1 Xenapp CAL = £170
• 1 terminal = £250
• ————————————————-
• Department of 30 people = £16,100
• Department of 50 people = £20,500

In the Xenapp Deployment costs you will notice that this does not include the costs of terminals to run the session on.

• 30 terminals = £7,500 + £16,100 = £24k
• 50 terminals = £12,500 + £20,500 = £33k

Comparison Table:-

Number Users                    30                       50                     1000

Physical PC £15k                  £25k                  £500k

Virtual Desktop £33k                  £43k                   £860k

Xenapp £24k                  £33k                  £660k

It’s very hard to detail the cost of ownership for each scenario as it depends on a number of contributing factors such as location of machines i.e. are they all in one place, 10 different branches or distributed across the country.

There are cost saving calculators on several vendors websites to help you with this task.

I used the vmware ROI TCO Calcualtor based on a comparion of virtualising 50 thick clients to vdi.  This take’s into account everything down to shared storage.



The Citrix ROI Tool based on the same 50 users returned

As you can see this is a lot less optimistic than vmware’s calculator in fact going from this you would not deploy a citrix vdi solution in a million years