TCO Comparison: Amazon WorkSpaces and Traditional Virtual Desktop Infrastructure (VDI)

Today, we announced Amazon WorkSpaces, a fully managed desktop computing solution in the cloud. Amazon WorkSpaces delivers a users documents, applications and resources to tablets, PCs, and Macs. The service has the benefits of on-premises VDI such as mobility and security combined with all the powerful AWS benefits such as pay-as-you-go and simplified management.

With Amazon WorkSpaces, you dont have to purchase, install, and maintain datacenter hardware or virtual desktop software. The Amazon WorkSpaces service does all this heavy lifting for you. With a few clicks of a mouse in the AWS Management Console, you can create your high-quality desktop experience for any number of users. The Amazon WorkSpaces service provisions a WorkSpace for each user and users can connect to their workspace using tablets, PCs, and Macs. When your organization grows and needs to scale with users, you do not need to procure new hardware or install new complex VDI software. You tell the service how many new WorkSpaces you need and what bundle to use. The service will provision the hardware based on the bundle configuration and provide a consistent high-quality desktop experience to each user. You pay only for the WorkSpaces you provision each month. When you need to turn off a users WorkSpace for example, a contractor leaves your company after completing her assignments you can stop paying for the WorkSpace at the end of the month.

Scenario (1000 Users)

To help you understand how cost-effective Amazon WorkSpaces is, we put together a Total Cost of Ownership (TCO) model for a scenario that delivers virtual desktop solution to users on-premises. In our model, we consider a 1000 user VDI solution. You can use this model as a starting point in your evaluation of virtual desktop solutions, and compare the TCO with a solution that uses Amazon WorkSpaces. Scaling this number up or down will impact the fixed cost per user.

Scenario Assumptions

For each user, we need to consider the computing experience we will deliver. We assume that the users are office workers who generally perform productivity tasks such as editing documents, building spreadsheets, browsing the intranet, sending e-mail, updating forms etc.

Now, if these users are going to use VDI, they need a solution that will allow them to save documents and settings, customize with their own applications, and have a persistent experience similar to a traditional desktop. To deliver this experience, we need a persistent virtual machine, with performance that is similar in perception to a traditional desktop. Users will also need dedicated storage for saving and retrieving their documents, with performance that is indistinguishable from using a local file store. To meet these requirements, we can size a virtual desktop as a virtual machine with 1 virtual CPU, 4 GiB of memory, and 50 GB of user data store. We also need to include storage for an OS volume, which we will assume adds another 50 GB.

Counting all the Costs

When determining the TCO of a cloud-based service, its easy to overlook several cost factors such as administration and license management costs, which can lead to an inaccurate and incomplete comparison. Additionally, in the case of a VDI solution, people often forget to include software costs. To obtain an accurate apples-to-apples comparison, you must include all of the different cost factors involved in deploying and managing a VDI solution, which means:

1. Server Hardware Costs – for hosting the virtual desktop and for managing the control plane for the system, you need server hardware to run Windows Server OS, Microsoft SQL Server Database and access gateways.
2. Storage Hardware Costs – you need Network-Attached Storage for persistent desktops.
3. Network Hardware Costs – you need networking gear to connect all the servers, storage, and control plane with users.
4. Hardware Maintenance Costs – hardware failures are unavoidable, so you will incur ongoing expenses for keeping the system functioning to spec.
5. Power and Cooling Costs – once the servers start running, you must consider the operational expenses of both powering and cooling the servers
6. Data Center Space Costs – you need real estate space to rack and stack the physical server
7. Software Costs to use VDI, you need VDI software that will allow you to set up and manage users, and their virtual desktop environments. While the software license costs might vary depending on the vendor you select, we believe their costs are comparable relative to the value they deliver.
8. Administration Costs setting up and managing hardware infrastructure, VDI environments and desktops is difficult and needs specialist IT staff. We believe you need at least two specialists per 1000 users to manage your desktop solution. We assume fully loaded cost of full-time IT specialist in the US is $150K/year. Your admin costs might vary based on your location and the experience levels of your staff.

Summary and Analysis

For a fair comparison, we have used amortized monthly costs. For example, hardware acquisition costs and administration costs are calculated per month. Typically, these costs are incurred upfront with long-term contracts. In our excel spreadsheet model, we clearly state our detailed assumptions for each cost item so you can adjust them based on your own research or quotes from your hardware vendors and co-location providers.

Based on the conservative assumptions highlighted above, for this particular scenario (of 1000 Users), you can clearly see that the Total Cost of Ownership of 1000 users using a desktop computing service such as Amazon WorkSpaces can be less than half the cost of running and managing an equivalent VDI solution on an on-premises infrastructure.

Aside from the cost savings you can obtain for a fixed number of users, the other important point to remember is that Amazon WorkSpaces creates savings for you by adapting to the needs of your business in a way that fixed investments simply cant. With Amazon WorkSpaces, you dont need to provision WorkSpaces for employees that you may never hire. On the other hand, if you grow your workforce, you can provision more WorkSpaces in minutes.

We are very excited about this new service and eagerly waiting to hear your feedback.

– Jinesh;