Extended the single-node log to work across multiple nodes with consistent ordering. Now we need to ensure all nodes see the same log sequence!
Distribute log operations across multiple nodes
Maintain consistent offset ordering globally
Replicate log entries for fault tolerance
Coordinate consumer offset commits
Multi-node logs need:
Global Ordering: All nodes must agree on message sequence
Consistency: Same offset = same message everywhere
Coordination: Who assigns the next offset?
Replication: How do we ensure durability?
Leader Election: One node coordinates offset assignment
Log Replication: Leaders replicate to followers
Consistent Reads: Route reads through current leader
Failover: Handle leader failures gracefully
Send: Forward to leader for offset assignment
Poll: Can read from any replica
Commit: Coordinate across nodes
Sync: Replicate log entries
Centralized offset generation for consistency
Async replication for performance
Read-your-writes consistency
Graceful leader failover
Pros:
Strong consistency guarantees
Fault tolerant through replication
Clear ordering semantics
Cons:
More complex than single node
Leader bottleneck for writes
Network coordination overhead
This gets us closer to real distributed log systems - the patterns here show up in Kafka, distributed databases, and consensus systems.
