{
  "slug": "write-quorum",
  "term": "Write quorum",
  "aliases": [
    "Write acknowledgement threshold"
  ],
  "definition": "A write quorum is a protocol-approved set of replicas whose acknowledgements satisfy the requirement for completing a write.",
  "note": "W is the acknowledgement threshold, not the number of destinations. Cassandra sends writes to all replicas, then waits for the configured consistency level. [cassandra] An acknowledgement's persistence meaning is a separate contract. [guarantees]",
  "limitations": [
    {
      "text": "A write timeout does not establish that no replica applied the mutation.",
      "citationIds": [
        "guarantees"
      ]
    }
  ],
  "related": [
    "read-quorum",
    "quorum-intersection"
  ],
  "citations": [
    {
      "id": "cassandra",
      "title": "Apache Cassandra 5.0.0: Dynamo architecture, tunable consistency and data versioning.",
      "url": "https://raw.githubusercontent.com/apache/cassandra/cassandra-5.0.0/doc/modules/cassandra/pages/architecture/dynamo.adoc",
      "accessed": "2026-10-13"
    },
    {
      "id": "guarantees",
      "title": "Apache Cassandra 5.0.0: Guarantees, including lightweight transactions.",
      "url": "https://raw.githubusercontent.com/apache/cassandra/cassandra-5.0.0/doc/modules/cassandra/pages/architecture/guarantees.adoc",
      "accessed": "2026-10-13"
    },
    {
      "id": "hesela-repair",
      "title": "Replica repair: what has actually converged?",
      "url": "https://hesela.com/analyses/replica-repair-coverage/",
      "accessed": "2026-10-13"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-13"
}