MongoDB Replication and HA Readiness

When to use

Invoke when standing up a replica set for production, restructuring members/elections, validating that the declared write/read concerns are actually survivable, sizing the oplog for failover, or placing replicas across regions.

Do not use for: document modeling, validators, or shard-key choice (use mongodb-data-model-and-migration); query/index tuning (use mongodb-indexing-and-query-optimization); backup, oplog-based PITR, restore drills (use mongodb-backup-and-operational-readiness); auth/RBAC/TLS/audit and internal-auth credentials (use mongodb-security-and-data-access-hardening); host, VM, or cluster provisioning (infrastructure layer — this skill designs the MongoDB topology, not the machines).

Inputs

Required:

• An existing data model from mongodb-data-model-and-migration (the per-operation read/write concern declarations this topology must be able to honor).
• Approved architecture/reliability availability targets and RPO/RTO per data tier, or explicit confirmation they are intentionally deferred.

Optional: