The Retirement Phase

The focus of the retirement phase is the successful removal of a system from production. Systems are removed from production for two basic reasons:

1. They are no longer needed. An example of this is a system that was put into production to fulfill the legal requirements imposed by government legislation. Now that the legislation has been repealed, the system is no longer needed.

2. The system is being replaced. For example, it is common to see homegrown systems for human resource functions replaced by commercial off-the-shelf (COTS) systems.

Activities of the retirement phase include the following:

1. A comprehensive analysis of the existing system to identify its coupling to other systems.

2. A redesign and rework of other existing systems so that they no longer rely on the system being retired. These efforts will typically be treated as projects in their own right.

3. Transformation of existing legacy data, perhaps via database refactoring (Ambler 2003b), because they will no longer be required or manipulated by the system being retired.

4. Archival of data previously maintained by the system that is no longer needed by other systems.

5. Configuration management of the removed software so that it may be reinstalled if required at some point in the future (this is easier said than done).

6. System integration testing of the remaining systems to ensure that they have not been broken via the retirement of the system in question.

The retirement, or sunsetting, of a system is often a difficult task that should not be underestimated.