ByteByteGo1 min readintermediate
Migrations at Scale: Changing the Application Engine at 30,000 Feet
Summary
The article outlines the challenges of swapping a production database without downtime and surveys common high‑level tactics—dual writes, feature flags, phased rollouts, and continuous sync—to keep the service available during large‑scale migrations.
- Use dual‑write or change‑data‑capture to keep old and new databases in sync during migration.
- Gate the new database behind feature flags and gradually shift traffic to validate performance.
- Employ backfill jobs that run in parallel to populate the new store while the old system remains live.
- Monitor latency and error rates closely; have a fast rollback path if the new system misbehaves.
Ops and backend engineers planning zero‑downtime database migrations need practical patterns to avoid service disruption.
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