A key factor for a successful data warehouse migration is in having a detailed preparation phase plan. The purpose of this plan is to ensure that you consider all the relevant topics that need to be handled during the migration. It also gives you a better basis for your time and budget estimations. At a high level, your preparation phase plan should cover some of the core aspects, such as:

Define Migration Team

Define Migration Strategy

Environment Assessment

Plan Iterations

The following sections provide you with more details on what to include in your preparation phase plan.