Exactly One Machine Accepts Writes, So Adding Machines Does Not Add Write Capacity
The curation's outcome depends on the learner internalising that the stateful tier does not obey the rule the replaceable tier taught them, and this is the node that states the rule it obeys instead. It sits directly on the entry floor's single-machine database and on the horizontal-scale idea the application sub-domain establishes. Everything downstream needs it: the vertical ceiling exists only because there is one writer, replicas make sense only as read capacity, and connection accounting matters only because every instance converges on one server.
Leader-Follower Database Replication for High Availability and Read Scaling
Database replication is the technique of maintaining multiple synchronized copies of a dataset to achieve high availability, fault tolerance, and scalability. In the leader-follower (primary-replica)…