This pattern is part of “Patterns of Legacy Displacement”
Stop the World cutover
Suspend normal business activities while cutting over to new system
This page is a stub. We intend to fully expand it in later revisions of this material. However we are still in the middle of developing these patterns, so it's likely that patterns will be renamed, split, or merged as we continue to learn how best to frame and explain these ideas.
It's still fairly common to see organizations use long outage periods, perhaps over a weekend, to perform a cut over to new systems. Here normal business activities are paused while cutover to the new system is performed. This often involves migration of data, reconfiguration of other systems to point to new integration points, update of DNS to point to new websites, and so on.
We've seen some large failures occur following this approach, often when no rehearsal or practice of the cut-over was possible or performed. Roll back in the event of a problem or overrun needs to be planned for. This approach can also create some very large peak loads as and when normal activities resume. Time for the cutover can be a large concern especially if revenue generation is interrupted during the cutover. We prefer more incremental approaches that allow migration of business to happen in smaller less risk increments.