By name: migration-strategies description: | Migration strategies: zero-downtime deployments, expand-contract schema changes, database migrations, framework migrations. Use when planning system migrations. allowed-tools: Read, Grep, Glob
Migration Strategies
When to use
- Planning zero-downtime schema changes or deployments
- Migrating from one framework/database to another
- Executing large-scale data migrations safely
Core principles
- Never big bang — incremental migration with rollback at every step
- Expand-contract for schema changes — add new, migrate, remove old
- Batch data migrations — 1000 rows at a time, 50ms delay between batches
- Test migration on production-size data — 100 rows works, 10M rows breaks differently
- Rollback plan before migration plan — if you can't roll back, you can't ship
References available
references/zero-downtime-migration.md— blue-green, canary, rolling with rollback proceduresreferences/database-migration-patterns.md— expand-contract, schema versioning tools (Flyway, golang-migrate, Prisma), safe migration rulesreferences/data-migration-patterns.md— dual-write between databases, batch ETL with cursor pagination, migration validationreferences/framework-migration.md— strangler fig pattern: CRA→Next.js, Express→Fastify, REST→GraphQLreferences/incremental-migration.md— step-by-step migration rules, rollback plans, shadow mode, monitoring during migration