{
  "slug": "data-durability",
  "term": "Data durability",
  "aliases": [
    "durability"
  ],
  "definition": "Data durability is the ability of a storage system to preserve data over a stated period and within a specified failure model.",
  "note": "Preserving data and maintaining access are different goals. An intact copy can outlive a failed access path without being immediately reachable by its host. The tolerated failures and recovery mechanism must be specified. [snia-durability-availability]\n\nObject-storage durability targets can be published alongside separate availability and zone-coverage properties. A target is not an observed loss sample, and equal target percentages do not establish equal disaster coverage. [aws-s3-classes]\n\nWhen comparing estimates, record whether the event is first loss or lost volume, and whether the denominator is objects, bytes or systems. The companion analysis separates those questions from access-error arithmetic.",
  "related": [
    "storage-availability",
    "mean-time-to-data-loss",
    "normalized-magnitude-data-loss",
    "failure-domain"
  ],
  "status": "unknown",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-22",
  "citations": [
    {
      "id": "snia-durability-availability",
      "title": "SNIA: NVM PM Remote Access for High Availability, May 2019, section 4.1, pp. 13-15 (non-normative whitepaper)",
      "url": "https://www.snia.org/sites/default/files/2024-12/SNIA-NVM-PM-Remote-Access-for-High-Availability-WP.pdf",
      "accessed": "2026-10-22"
    },
    {
      "id": "aws-s3-classes",
      "title": "AWS S3 User Guide: storage-class design targets and zone coverage",
      "url": "https://docs.aws.amazon.com/AmazonS3/latest/userguide/storage-class-intro.html",
      "accessed": "2026-10-22"
    }
  ],
  "provenance": [
    "Conceptual definition; not a claim of measured reliability. The SNIA source discusses persistent-memory recovery, not a certification for all storage systems."
  ]
}