Agile, SAAS, NFRs & Architecture

For quite sometime I have been trying to get a grip of the agile methodology to develop applications. Somehow I am not 100% convinced (although I am 90% convinced) that Agile is the way forward.
I am still in a state of mind that Agile does not solve 100% of all the software development problems. This article is my effort to highlight few of my view points on this subject.

Agile : I would not go any deep in to this topic as it is a known and a well established topic.
If would like to know more about Agile, there are tons of articles on this subject. All you would need to do is google or (in Microsoft terms) bing it :-)

The Agile Mantra says...

• Individuals and Interactions - over process and tolls
• Working software - over comprehensive documentation
• Customer collaboration - over contract negotiation
• Responding to change over following a plan

In short Agile means - "Iterative Design & development".

So far so good.

But the key point to note here is - its "Design & Development". The process starts at "Design".

For large scale systems such as high availability, high concurrency, highly scalable systems, the key way forward starts at "Architecture". May be there are cases where a good Design does not require a strong architecture pre-thought but not always the case.

Architecture is NOT Design. Architecture is a process of looking at the entire system from a high level and providing a blueprint of how large scale systems are built.

Architecting a complex product such as a SAAS offering goes beyond just designing. SAAS systems invariably has stringent Non Functional requirements such as Availability (99.99% uptime), Scalability (x Thousand Concurrent users), High Performance response times (X transactions per second), Configurability (Meta data driven configuration), Extensibility (NOT CODE extensibility but product extensibility).

All the above elements have to be well thought of for a successful implementation of a high performance solution such as a SAAS offering.

As the name suggests, these are "NON-FUNCTIONAL REQUIREMENTS". They cannot be "automatically" captured as "User stories". Even if we capture these things as a part of User stories, which sprint do these stories belong to? How do we cater to this in a particular sprint? Should this be pushed to the last sprint? How do you split these requirements within each sprint? Most applications (even enterprise scale) may not worry much about these non-functional requirements. An enterprise application can wait for a half hour down time but a SAAS system, these things are fundamental. A SAAS system is a different game all-together.

There is no doubt that Design and development is key to any software development. But equally important is Architecture. This makes me wonder if there is something called as a 100% pure Agile project? If there is a 100% pure agile project, can this be used to build a SAAS solution with stringent NFRs?

To my mind the answer is NO. The first 10-20% of the time goes in conceptualising and "architecting" the system and then the system can be developed in Sprints (which is rest of the 80%). Architectural Patterns such as Zachman, RM-ODP, Rational Unified Process etc. (or fr that matter any Architectural patterns) wouldn't have existed if it had no use and the same can be done using a Agile methodology by directly jumping into design and development.

I am not sure how this article will be received, but this is just an attempt I thought I should make share my mind to fellow architects in the software world. I do love Agile. Agile is the way to go. There is no doubt about that.

The attempt here is to highlight the fact that - "There is nothing called as 100% agile software development"

Especially if you are thinking of developing a SAAS solution with extremely stringent NFRs, ensure you cover these NFRs within your Architecture and then start development using any Agile methodology.

For an Agile evangelist, a product development life cycle is - Sprint + Spint + Sprint + Sprint.

To my mind it is - Conceptualising & Detailed Architecture + Sprint + Sprint + Sprint + Sprint.

As I have been emphasizing, I am not sure if this arcticle would be well received by Agile Evangelist, but I thought this could be a good food for thought.

I have been involved in building SAAS applications with Stringent NFRs and hence I am able to relate this to agile development.

Await for my next blog on NFRs and its importance in designing a software solution.