Migration is a challenging project for many. With the Cloud model, there are plenty of migration to and fro on premises and Cloud. Some will try to migrate to a ERP type large global system only to find its constraint. Then, they will migrate it back to legacy. One common trend in these migration is often traditional approach. Instead, you can consider to adopt Agile migration.
Traditional migration adopt incubator or sandbox approach. It involves a waterfall model of Big Bang. Initial fixes are done in the upgraded system with sample data. Changes are then deployed accordingly to testing environment for UAT (User Acceptance Testing). Once signed off, the entire fixes are deployed in a Big Bang to production environment. For each fix, regression testing are conducted again from testing environment. Duration of project will be at least 6 months to a year.
Agile migration are pioneered by the Cloud trend. Lift and Shift is the most common migration approach. In this case, at least 3 cyclic runs are performed on the migrated production environment. Agile is adapted for the project approach. The duration is shorter and takes less than 6 months. Another Agile approach is incremental migration. Migration is done incremental or Agile to move from legacy to target system.
Many organisations or vendors will conform to traditional migration approach to mitigate risks. With growing trend of Cloud and Agile team, you can consider to use Agile migration. The Agile approach aims to minimise costs and duration. However, you do required experienced vendors and SME (Subject Matter Expert) to adopt this strategy.