{
  "slug": "partial-quorum",
  "term": "Partial quorum",
  "aliases": [
    "Non-strict quorum"
  ],
  "definition": "A partial quorum configuration allows a read response set and a write acknowledgement set that need not overlap.",
  "note": "With uniform R- and W-member subsets of the same N replicas, non-intersection has probability C(N-W,R)/C(N,R); missing all k recent writes raises it to the kth power only under independent write selections. [pbs] Partial concerns overlap, whereas sloppy quorum concerns fallback membership. [dynamo]",
  "limitations": [
    {
      "text": "This sampling model is not a production stale-read rate or a deterministic time bound.",
      "citationIds": [
        "pbs"
      ]
    }
  ],
  "related": [
    "quorum-intersection",
    "sloppy-quorum"
  ],
  "citations": [
    {
      "id": "pbs",
      "title": "Bailis et al. Probabilistically Bounded Staleness for Practical Partial Quorums. PVLDB 5(8), 776-787 (2012), equations 1-2.",
      "url": "https://www.vldb.org/pvldb/vol5/p776_peterbailis_vldb2012.pdf",
      "accessed": "2026-10-14"
    },
    {
      "id": "dynamo",
      "title": "DeCandia et al. Dynamo: Amazon's Highly Available Key-value Store. SOSP 2007, sections 4.5-4.6.",
      "url": "https://www.allthingsdistributed.com/files/amazon-dynamo-sosp2007.pdf",
      "accessed": "2026-10-14"
    },
    {
      "id": "hesela-model",
      "title": "Hesela: exact partial-quorum examples, assumptions and executable source",
      "url": "https://hesela.dev/data/partial-quorum-examples.json",
      "accessed": "2026-10-14"
    }
  ],
  "status": "research",
  "advantages": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-14"
}