Evidence level: historically reviewed source and owner proposals; not freshly tested or certified for production.
Design and implementation invariants
- The third YSQL node handles its assigned placement phase but cannot claim independent host-level durability.
- A configured replication factor is not equivalent to a live, independently validated disaster-recovery result.
Verification still required
- Prove real tablet placement, quorum, safe placement changes and physical-failure behavior.
- Off-host backup and restore evidence belongs to Backup Coordinator, not to logical YSQL placement checks.
How to update
When the owner changes implementation or contract behavior, update this page and the relevant service interfaces. For cross-service changes, also update the platform interface map or decision register. State the actual verification performed; do not inherit historical pass claims without fresh evidence.