Unix Application Migration Guide (Patterns & Practices)

When you have completed the assessment and have made a decision about the strategy for the migration, you can plan the necessary steps for beginning the migration. This planning stage involves the definition of objectives and schedules for the migration so that you can find the appropriate resources and allocate tasks as necessary.

The activities involved in planning can be grouped into starting the project, developing a catalog of issues, and drafting a project plan. The project plan should be as accurate as possible at this point in the mitigation project. However, do not attempt to produce a plan that is too detailed, because the scope of the migration may change after porting or rework activities are underway.

Planning is covered in more detail in Chapter 5, Planning the Migration.

Starting the Migration Project

The migration project has already started, in that assessment and analysis activities are ongoing. When these are complete, initiate a plan for the migration itself. You can then establish key criteria for the mitigation, and may actually discover that a single assessment and analysis process can accommodate multiple migration projects.

The following are essential start-up activities:

• Establish the project scope

  Make sure that the requirements for the migration are well defined and bounded. Otherwise, other application elements may be drawn into the migration, which can create a migration-project overrun .

• Establish the resources

  Determine the available resource levels for the migration project. Because it is unlikely that infinite resources are available, migration activities can be limited to the available personnel and budget resources.

• Document the success criteria

  Arrive at a consensus about the project success criteria with the project stakeholder or user representative to ensure a basis for agreement about when the project is complete.

• Determine the preliminary schedule

  It may not be possible to determine a definitive schedule until after the plan has been produced, and the schedule may need to be changed after the project is underway. However, preliminary deadlines are useful in the planning process.

Developing a Catalog of Issues

Throughout the assessment stage, you document issues that can or should influence the migration. The issues may be schedule related to business, technical, application, or infrastructure aspects of the application or the overall mitigation project. Before you can create a realistic project plan, you must determine whether any of the issues pose a serious risk to the project, and what can be done to minimize the possibility of those risks.

You may want to investigate the following issues:

• Business issues

  • The impact of the change on the end-users

  • The shortfall between the application functionality and user need

  • The distribution of the user base

• Technical issues

  • The experience required to perform the migration

  • The technical complexity of the solution

  • The security requirements

  • The application deployment

  • The dependency or effect on other applications

• Application issues

  • The quality of the code and scripts

  • The quality of the development environment (for example, source control, configuration, build, debugging, and bug tracking)

  • The required service levels for the application

  • The standards conformance requirements

• Infrastructure issues

  • The hardware performance

  • Interoperability and integration

A more complete list of potential issues is presented in Chapter 5, Planning the Migration.

Each issue can create a number of risks in the project. Those risks can be quantified in terms of probability and impact. You should determine mitigation actions for each risk to ensure that the risk is minimized or removed.

Producing a Project Plan

The migration project plan should take into account the type of migration to be performed, the issues that are identified (and the mitigation for the issues), the funding provided, and the availability and skills of the people who are assigned to the migration project. The project plan is based on the project stages described in this document, and the activities involved in each stage vary according to the chosen migration strategy.