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Replication Trade-offs

Copying data to multiple nodes improves availability and read throughput but introduces consistency challenges - synchronous replication ensures consistency at cost of latency and availability; asynchronous replication provides speed but risks data loss and staleness.

Tension Addressed

Consistency vs. Latency (and Consistency vs. Availability)

Recognizable As

Primary-replica configurations; synchronous vs. async replication settings; replication lag monitoring; read-your-writes guarantees; eventual consistency warnings

Canonical Sources

Gray et al., "The Dangers of Replication and a Solution" (1996); Helland, "Building on Quicksand" (2009)

Transfers To

Database architecture, CDN design, cache strategies, disaster recovery, geographic distribution

Sub-concepts: - Synchronous replication: Write confirmed only after all replicas acknowledge; strong consistency, higher latency - Asynchronous replication: Write confirmed immediately, replicated in background; lower latency, risk of data loss - Semi-synchronous: Write confirmed after some (not all) replicas acknowledge; compromise position