Zero downtime migrations at petabyte scale
Summary
PlanetScale describes a zero-downtime migration approach for petabyte-scale data, focusing on migrating to PlanetScale with PostgreSQL support and Vitess primitives. The piece outlines a multi-step process: non-locking snapshots, continuous replication, VDiff verification, traffic routing and buffering, and a reversible cutover using MoveTables, with emphasis on fault tolerance and the ability to revert if needed. It also discusses sharding strategies and practical considerations for large-scale migrations.