When should one use the following: Amazon EC2, Google App Engine, Microsoft Azure and Salesforce.com?

Question

I am asking this in very general sense. Both from cloud provider and cloud consumer\'s perspective. Also the question is not for any specific kind of application (in fact the in

Answer 1

The major points of cloud computing is to save on costs by paying for usage and enable immediate deployment of computing resources.

The costs are not purely x amount of cents per instance per hour. The costs include maintenance, development, administration, etc. The huge benefit of cloud, in my mind is to liberate the customers from having to manage anything that is not within the realm of their core business competency. If I am an insurance business, I want my developers to concentrate on my insurance problems that help solve needs of my claims, rates, etc. I would rather avoid dealing with problems of email servers, file servers, document repositories, and administrating OS patches, service packs, etc.

Thus, in my opinion, the biggest benefits are derived from the SaaS and PaaS cloud offerings. One should go to IaaS only when PaaS or SaaS have serious restrictions to specific needs (i.e. I need to install a set of proprietary COM components and Azure does not support them).

SaaS is good for commodity type of applications that are not the core line of business for the client, but are more of a utility. These are your typical Messaging systems, Portals, Document Repositories, Email systems, CRMs, ERP's, Accounting, etc. etc. etc. Why reinvent the wheel by writing your own when you can customize a well supported third party product.

PaaS is great for core line of business software that supports companies' main business offering. Abstracts clients from having to deal with OS management and lets clients concentrate on the business system development - something that noone else can do for the client.