{
  "slug": "normalized-magnitude-data-loss",
  "term": "Normalized magnitude of data loss (NOMDL)",
  "aliases": [
    "NOMDL"
  ],
  "definition": "Normalized magnitude of data loss (NOMDL) is the expected number of bytes lost per usable terabyte within a stated mission time.",
  "note": "Greenan, Plank and Wylie proposed NOMDL in 2010 to report loss magnitude and capacity together. [greenan-hotstorage10-pdf] The time horizon and underlying model must accompany the value; normalization does not validate failure assumptions.",
  "related": [
    "mean-time-to-data-loss",
    "failure-domain",
    "erasure-coding"
  ],
  "status": "research",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-15",
  "citations": [
    {
      "id": "greenan-hotstorage10-pdf",
      "title": "Mean time to meaningless: MTTDL, Markov models, and storage system reliability, Greenan, Plank, and Wylie, USENIX HotStorage 2010 (USENIX PDF, independent academic source)",
      "url": "https://www.usenix.org/legacy/event/hotstorage10/tech/full_papers/Greenan.pdf",
      "accessed": "2026-10-15"
    },
    {
      "id": "hesela-durability",
      "title": "Eleven nines: what a durability model does not prove",
      "url": "https://hesela.com/analyses/s3-durability-eleven-nines-derivation/",
      "accessed": "2026-10-15"
    }
  ]
}