WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

4.1 Infrastructure planning
This section gives a general overview of the typical phases you have to go
through during a project. It includes how to gather requirements and how to apply
these requirements to a WebSphere Application Server project.
Typically, a new project starts with only a concept. Little is known about specific
implementation details, especially how they relate to the infrastructure. Your
development team and infrastructure team must work closely together to cater to
the needs of the overall application environment.
Bringing together a large team of people can create an environment that helps
hone the environment requirements. However, if unfocused, a large team can
wander aimlessly and create more confusion than resolved issues. For this
reason, carefully consider the size of the requirements gathering team and try to
keep the meetings as focused as possible. Provide template documents to be
completed by the developers, the application business owners, and the user
experience team.
Try to gather information that falls into the following categories:
► Functional requirements
Functional requirements are usually determined by business on the use of the
application and related functions.
► Non-functional requirements
Non-functional requirements describe the properties of the underlying
architecture and infrastructure such as reliability, scalability, availability, or
security.
► Capacity requirements
Capacity requirements include traffic estimates, traffic patterns, and expected
audience size.
Requirements gathering is an iterative process. Make sure that your plans are
flexible enough to deal with future changes in requirements Always keep in mind
that the plans can impact other parts of the project. To support this, make sure
that dependencies and data-flows, whether application or infrastructure-related,
are clearly documented.
94 WebSphere Application Server V7.0: Concepts, Planning, and Design