ozerohax/templates/skills/planning/migration-strategy

<purpose> <item>Design a migration that preserves data integrity and compatibility</item> </purpose> <inputs> <required>What we migrate (schema/data/API) and why</required> <optional>Data volume, time windows, downtime constraints</optional> <optional>Backward-compatibility requirements</optional> </inputs>

<common_patterns> <pattern>expand/contract</pattern> <pattern>dual-read / dual-write</pattern> <pattern>backfill in background</pattern> <pattern>versioned API / events</pattern> </common_patterns>

<method> <step>Identify migration objects and dependencies (tables, indexes, consumers)</step> <step>Select a migration pattern and justify it (why it fits the constraints)</step> <step>Split into phases: preparation -> compatibility -> transfer -> cutover -> cleanup</step> <step>Define integrity/correctness verification (checksums, counts, sampling)</step> <step>Explicitly describe compatibility during the migration window (which versions coexist)</step> </method>

<output_format>

<section>Migration objects</section> <section>Chosen pattern + rationale</section> <section>Phases</section> <section>Compatibility window</section> <section>Data verification</section> </output_format>

<quality_rules> <rule importance="critical">Data integrity verification exists (not only "ran the migration")</rule> <rule importance="high">Compatibility during the migration window is described explicitly</rule> </quality_rules>