Anti-Entropy Protocols

1. Overview

Definition:
- Anti-entropy protocols are methods used in distributed systems to ensure data consistency across nodes.
Purpose:
- They help reconcile differences between replicas, particularly in systems where data may diverge due to concurrent writes or network failures.
Mechanisms:
- These protocols typically involve periodic checks of data states across nodes, followed by synchronization to resolve discrepancies.
Types:
- Push-based: One node sends its data state to others.
- Pull-based: Nodes request updates from one another.
- Hybrid: Combines both push and pull mechanisms.
Application:
- Commonly used in distributed databases (e.g., Dynamo, Cassandra) and peer-to-peer networks.
Challenges:
- Latency: Ensuring prompt updates can be difficult in large networks.
- Network Partitioning: Handling situations where network splits can lead to divergent state.
- Performance: Balancing consistency checks without overloading the system.