How to Migrate Without Stopping Operations
Migration risk can live in both the data and the operation itself, especially during the period when the team has to work in two systems at once.
The Two Risks People Confuse
The technical risk — that the data doesn't arrive complete or correct — is real, and can be reduced with method: mapping, testing, and reconciliation.
The operational risk — that the team can't work during the transition — can stop projects, and deserves the same attention as the technical risk.
The Risks of a Full Cutover
Changing everything over one weekend concentrates several conditions for success at the same time: that processes are ready, that the old system is no longer needed, and that no unexpected complications come up.
If the old system stops receiving new data, a failure during the cutover can make it difficult or impossible to go back to how things were.
Migrate by Domain, Not by System
One alternative is to move one domain at a time — billing, for example — and keep the rest where it is until that domain is working.
The temporary coexistence between systems can be uncomfortable, but it lets you spread the transition out instead of concentrating it all into a single day.
Three Questions Before You Start
- What's the single source of truth for each piece of data during that coexistence? If two systems can both modify the same data, the migration can be at risk.
- How do you go back? If there's no answer, there's no plan — there's a bet.
- Who decides it's finished? Without an explicit definition of done, a migration can drag on or stay incomplete.