If problems occur during the migration, your plan should cover actions to take.

The plan should consider the severity of any potential problems and recommend appropriate action. For example, in a worst-case scenario it might be necessary to back out the migration entirely. The strategy should also consider how long the migration is in place before it can be considered irreversible.

To back out a migration it may be necessary to have secured the original version of the system. The plan should specify what data to back up, including transactional, static, and configuration data, and the methods employed to do so.