{
  "slug": "stable-storage",
  "term": "Stable storage",
  "aliases": [],
  "definition": "Stable storage preserves data through a specified set of failures and supports recovery without losing the data it has committed.",
  "note": "For NFSv4.1, RFC 8881 section 1.7 covers repeated power interruptions, including closely spaced failures, operating-system failures and failures of components other than the storage medium. Failure of that medium is excluded. [nfs41]\n\nThe implementation can use protected intermediate storage with recovery software; stable does not require every byte acknowledged as stable to be on its final disk surface. [nfs41]\n\nSNIA separately identifies single non-media hardware failures, repeated software crashes and a required period without external power. State the applicable contract and retention interval; the dictionary does not assign one universal number of hours. [snia]\n\nA persistence domain identifies protected components; stable storage specifies the recovery guarantee. Neither label alone certifies a particular appliance.\n\nThe 1979 Lampson-Sturgis construction uses two copies outside a shared modeled decay set, ordered verified writes and recovery cleanup. Undetected corruption and overly frequent decay are excluded from its assumptions; two copies alone do not establish its guarantee. [stable-lampson-sturgis]",
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "related": [
    "nfs-commit",
    "persistence-domain",
    "power-loss-protection",
    "nvram",
    "data-durability"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-13",
  "citations": [
    {
      "id": "nfs41",
      "title": "Noveck and Lever (editors). RFC 8881, NFSv4.1, section 1.7: Stable Storage.",
      "url": "https://www.rfc-editor.org/rfc/rfc8881.html#section-1.7",
      "accessed": "2026-11-12"
    },
    {
      "id": "snia",
      "title": "SNIA Dictionary: stable storage; failure classes and powerless-retention scope.",
      "url": "https://www.snia.org/education/online-dictionary/term/stable-storage",
      "accessed": "2026-11-12"
    },
    {
      "id": "hesela-nfs",
      "title": "Hesela. NFS stable writes: what COMMIT, flush and FUA actually promise.",
      "url": "https://hesela.com/analyses/nfs-stable-writes-flush-fua/#stable-failures",
      "accessed": "2026-11-12"
    },
    {
      "id": "stable-lampson-sturgis",
      "title": "Butler W. Lampson and Howard E. Sturgis. Crash Recovery in a Distributed Data Storage System. working paper, 1 June 1979, sections 4.1 and 5.1 (pp. 6-7, 10-12).",
      "url": "https://pages.cs.wisc.edu/~remzi/Classes/739/Papers/lampson-sturgis-79.pdf",
      "accessed": "2026-11-13"
    }
  ],
  "provenance": [
    "Primary-source definition review. Appliance compliance and recovery behavior are not measured; no universal retention duration is inferred."
  ]
}