Replication Topologies
1 min read
Choose single-leader, multi-leader, or leaderless replication based on availability and consistency needs.
Choose single-leader, multi-leader, or leaderless replication based on your availability and consistency requirements.
How It Works
Replication copies data across multiple nodes. Single-leader: one node accepts writes, replicas serve reads. Multi-leader: multiple nodes accept writes, requires conflict resolution. Leaderless (Dynamo-style): any node accepts reads and writes, uses quorum (W + R > N). Match topology to consistency requirement: strong -> single-leader, available -> leaderless, multi-region -> multi-leader.
Real-World Example
Cassandra uses leaderless replication with configurable consistency. For a social media "like" counter, quorum writes (W=2 of 3) and quorum reads (R=2 of 3) guarantees seeing the latest write while tolerating one replica being down.
Test Yourself
Scenario: A SaaS app is 80% reads, 20% writes, with users distributed across 5 regions. Which replication topology do you pick, and what do you give up?
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