{
  "slug": "git-alternate-object-database",
  "term": "Git alternate object database",
  "aliases": [
    "Git object alternates"
  ],
  "definition": "A Git alternate object database is an additional object directory that a repository searches for objects it does not store locally.",
  "note": "Lookup scope: objects/info/alternates and GIT_ALTERNATE_OBJECT_DIRECTORIES can make objects available outside the repository's own object directory; full fsck includes these stores. A passing check therefore does not establish that a copied directory is self-contained. [git-fsck]\n\nCopy independence: clone --shared can borrow objects from its source. Repack without --local can copy borrowed reachable objects; local-only repacking deliberately excludes them. The --dissociate clone option breaks borrowing after transfer, but object-provider independence is separate from physical-media independence. [git-clone] [git-pack-local]\n\nMeasured boundary: in Hesela's Git 2.43.0 fixture, shared and local-repacked copies failed after their provider pathname became unavailable while their own file hashes remained unchanged. Full-repack and dissociate controls remained readable. This is a controlled provider-disconnection test, not a garbage-collection or device-failure measurement. [hesela-git]",
  "status": "shipping",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-19",
  "advantages": [
    "Allows object reuse without immediately duplicating an entire object store."
  ],
  "limitations": [
    "Availability can depend on an external repository and its object retention policy."
  ],
  "related": [
    "git-bundle",
    "backup-verification",
    "restore-test",
    "deduplication"
  ],
  "citations": [
    {
      "id": "git-clone",
      "title": "Git v2.43.0: shared clones, local repacking and dissociation",
      "url": "https://github.com/git/git/blob/v2.43.0/Documentation/git-clone.txt",
      "accessed": "2026-10-19"
    },
    {
      "id": "git-fsck",
      "title": "Git v2.43.0: full and connectivity-only object checks",
      "url": "https://github.com/git/git/blob/v2.43.0/Documentation/git-fsck.txt",
      "accessed": "2026-10-19"
    },
    {
      "id": "git-pack-local",
      "title": "Git v2.43.0: pack-objects --local",
      "url": "https://github.com/git/git/blob/v2.43.0/Documentation/git-pack-objects.txt",
      "accessed": "2026-10-19"
    },
    {
      "id": "hesela-git",
      "title": "Hesela: Git backup dependency and verification controls",
      "url": "https://hesela.com/analyses/backup-verification-is-not-a-restore-test/#git-backup-closure",
      "accessed": "2026-10-19"
    }
  ],
  "provenance": [
    "Versioned Git documentation and disposable native-Git 2.43.0 controls; no fleet failure-rate estimate."
  ]
}