Postgres Replication and HA Readiness

When to use

Invoke when a PostgreSQL deployment has a stated availability or RPO/RTO target, when designing the replication topology for a new service, when validating an existing topology before a reliability review or scale event, or when remediating failover, split-brain, or replica-lag problems.

Do not use for: schema modeling or migrations (use postgres-schema-and-migration), query/index performance (use postgres-indexing-and-query-optimization), backup/PITR/restore drills (use postgres-backup-and-operational-readiness), or role/grant/TLS hardening (use postgres-security-and-data-access-hardening).

Inputs

Required:

• The reliability targets in scope: availability SLO, RPO, RTO, and the failure domains that must be survived. Sourced from reliability-architecture.md where it exists.
• The replica topology decision and consistency posture from data-architecture.md (single-primary, read replicas, multi-region, sync vs async expectation).
• The deployment substrate: self-managed (Patroni/repmgr), managed (RDS/Aurora/Cloud SQL Multi-AZ), or Kubernetes operator.

Optional: