Hi Guys:

We have an enterprise level IT Service Management Application (Help Desk) on ASP.NET which we are now planning to launch in the cloud as SaaS (Software as a Service).  We are in the planning phase and need the community's help.

we would like customers to signup for the application on our website. Upon signup, customers will choose their application url which would be a sub domain on our website. Once they signup, there will be an automated process which will configure the sub domain and setup their application instance on DotNetNuke. There would be virtually an unlimited number of customers who will be signing up.

 Here are the things we are confused about:

a. which service shall we go for (Amazon AWS , Windows Azure or another hosting provider)? we need high scalability infrastructure with automation.

b. How should we handle multiple client portals on a single server ?(multiple portals on a single DNN Instance or separate DNN instance for each customer)

c. Shall we go for multiple servers with low resources and small number of portals per server or a single server with High Resources and all portals on the same server?

d. Which options will be most performance and cost effective?

e. How can we handle the increase and decrease in resource requirements, can we implement a monitoring engine which could automatically handle resources based on demand?

Really appreciate the community's expert guidance on the above mentioned questions.

 Thanks.

 Umer