Store migrationer – ny database, nyt framework, ny platform – er højrisiko, fordi de påvirker alt og leverer ingen synlig værdi for brugerne, før de er gennemført. Den sikre tilgang er inkrementel og reversibel, aldrig en big-bang-cutover. Du migrerer i skiver, som du kan validere og rulle tilbage.
En sikker migrationsspillerebok
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1. Know WHY — a migration with no clear payoff isn't worth the risk.
2. Migrate INCREMENTALLY — never flip everything at once.
3. Run OLD and NEW in parallel — strangler-fig pattern.
4. Use feature flags / DUAL WRITES to shift traffic gradually.
5. VERIFY continuously — compare old vs. new outputs (shadow traffic).
6. Keep a ROLLBACK path at every step.
7. Clean up the old system only AFTER the new one is proven.