Windows Azure is here and it reshapes the IT landscape. Even if technology will ultimately make the on-premise and cloud offerings symmetrical from a technological point of view, it will remain a challenge to calculate and compare the total cost of ownership of a solution if it would run in the cloud or on-premise.
Applications are being deployed to Windows Azure today. you can find a list of them on Pinpoint: http://pinpoint.microsoft.com/en-US/windowsazure/resources
Certainly there must be good reasons to run these applications in the cloud instead of locally and certainly price comparisons have been made. But how?
There are companies specializing in this. And they can give you deep advise. But to start you can use this online TCO calculator to give you an initial idea and understanding of the major components in such a calculation.
The tool asks you a number of questions which give you insight in the axises along which the cost for your solution will be measured. Currently these include:
- Development Application (Exisiting or old application, .Net or other)
- Size of the application or service (small; medium, large; you are basically asked on how many machines, like webservers, this would typically run)
- SQL Database (yes, no)
- Integration (Highly –>not; basically asking about the number of messages this application or service will exchange with other services applications)
- User logins (Heavy, medium, light, no; more than a million –> no)
- Growth profile of the application (see image above)
Based on that information the calculator will measure which services your app will be using and how that will induce a cost on processor hours, storage size, bandwidth used and messages sent and will give you a price
For my personal small, new application with database, few users, low integration and steady growth, there ROI looks great but of course I urge you to make the exercise for a couple of scenarios yourself.