Backend & systems·Consistency and replication
all writes go to one node and the other copies exist only to be read from and to be promoted if it dies.
Leader-follower replication
Also calledprimary-replica, single-leader replication, master-slave
The standard topology: one node accepts writes and streams its change log to read-only followers. It avoids write conflicts entirely because there is only one writer. Write throughput is capped by that one node, and every failover is a moment where you must decide between waiting and losing data.