On a specific request from one of our customers, we recently did a detailed analaysis of the various alternatives of building and migrating a SaaS application on .NET, their relative costs and TCO.

The first part of the analysis is to compare the development and deployment costs of a multi tenant application @ Maturity Model 2 and 4. We used the cost of Amazon EC2 instance as a reference.  In a MMM 2 application, a separate instance is required for every new customer / tenant. Whereas in a MMM 4 application, the same instance can be used to support multiple tenants / customers. However the development cost of a MMM 4 application is more than that of a MMM 2 application. So the analysis is to find whether it makes sense to invest in the additional development time to save on the deployment costs. The no. of tenants was assumed to be 50 which is a very conservative number even for a start-up ISV.

The second part of the analysis was a build vs buy comparison for a Multi-tenant SaaS Framework. The in-house framework development and maintenance cost was compared with the licensing costs and AMC costs of a ready to use framework such as celloSaaS.

We then kept the 3 year TCO of a New Multi-tenant (MMM 4) application as the reference cost and calculated the % saving of all the other alternatives.

Migration of an existing .NET application was also considered. Assuming a code re-usability of 50%, we calculated the relative merits of hosting the existing application on Apprenda’s SaaSGrid PaaS viz-a-viz migrating it to a Multi-tenant maturity model 4 at the application level. (with and without celloSaaS)

You can download this excel sheet from our website (Download section), plug and  play with your own nos. and calculate the relative merits of each alternative.