{
  "slug": "nfs-write-gathering",
  "term": "NFS write gathering",
  "aliases": [
    "NFS write clustering"
  ],
  "definition": "NFS write gathering combines related server writes to share persistence work before sending their replies.",
  "note": "Juszczak's 1994 implementation preserves stable completion and is not an unstable acknowledgement scheme. [juszczak1994]\n\nThe Linux exports manual documents wdelay/no_wdelay: delaying related requests can share disk work, but unrelated small writes may suffer; no_wdelay has no effect with async. This option documentation does not establish that a current kernel uses the historical implementation. [exports]",
  "status": "shipping",
  "advantages": [
    {
      "text": "Can amortize work across related requests.",
      "citationIds": [
        "exports"
      ]
    }
  ],
  "limitations": [
    {
      "text": "A batching delay can penalize workloads with little opportunity to combine writes.",
      "citationIds": [
        "exports"
      ]
    }
  ],
  "related": [
    "nfs-storage",
    "nfs-commit",
    "group-commit",
    "write-back-cache"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "juszczak1994",
      "title": "Chet Juszczak. Improving the Write Performance of an NFS Server. USENIX Winter 1994, sections 2, 6.8, 6.10 and 7.1; Tables 1-2 (PDF p. 8).",
      "url": "https://www.usenix.org/legacy/publications/library/proceedings/sf94/full_papers/juszczak.pdf",
      "accessed": "2026-10-17"
    },
    {
      "id": "exports",
      "title": "nfs-utils exports(5), Debian trixie: sync, async and no_wdelay/wdelay.",
      "url": "https://manpages.debian.org/trixie/nfs-kernel-server/exports.5.en.html",
      "accessed": "2026-10-17"
    },
    {
      "id": "hesela-stability",
      "title": "NFS stable writes: historical write-gathering evidence and benchmark boundaries",
      "url": "https://hesela.com/analyses/nfs-stable-writes-flush-fua/#gathering",
      "accessed": "2026-10-17"
    }
  ],
  "updated": "2026-10-17"
}