{
  "slug": "application-quiescing",
  "term": "Application quiescing",
  "aliases": [
    "Application quiescence",
    "Application quiesce"
  ],
  "definition": "Application quiescing is application-specific preparation and temporary restriction of writes to establish a defined state for snapshot or backup capture.",
  "note": "VSS writers illustrate this coordination by preparing application state before filesystem freezing. [microsoft-vss] QEMU can invoke a configured hook with freeze and thaw arguments, but configuration alone does not establish successful preparation or resumption of every application. [qemu-hooks] The QEMU v10.1.0 example wrapper exits zero when its hook directory is absent and skips non-executable hooks, so a successful wrapper exit does not prove that an application hook ran. [qemu-example-hook] Verify preparation and resumption separately from storage capture.",
  "status": "shipping",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-15",
  "advantages": [
    {
      "text": "Allows application-specific preparation before a snapshot is established.",
      "citationIds": [
        "microsoft-vss"
      ]
    }
  ],
  "limitations": [
    {
      "text": "Depends on participating applications and their supported backup procedure.",
      "citationIds": [
        "microsoft-vss"
      ]
    },
    {
      "text": "A configured guest-agent hook does not independently prove application-level success.",
      "citationIds": [
        "qemu-hooks"
      ]
    }
  ],
  "related": [
    "application-consistent-snapshot",
    "filesystem-freeze",
    "snapshot",
    "backup",
    "restore-test"
  ],
  "citations": [
    {
      "id": "microsoft-vss",
      "title": "Microsoft: Volume Shadow Copy Service, application writers and snapshot coordination",
      "url": "https://learn.microsoft.com/en-us/windows-server/storage/file-server/volume-shadow-copy-service",
      "accessed": "2026-10-15"
    },
    {
      "id": "qemu-hooks",
      "title": "QEMU Guest Agent: fsfreeze hook configuration",
      "url": "https://www.qemu.org/docs/master/interop/qemu-ga.html#cmdoption-qemu-ga-F",
      "accessed": "2026-10-15"
    },
    {
      "id": "qemu-example-hook",
      "title": "QEMU v10.1.0 example fsfreeze hook: missing directory and executable hook checks",
      "url": "https://github.com/qemu/qemu/blob/v10.1.0/scripts/qemu-guest-agent/fsfreeze-hook",
      "accessed": "2026-10-15"
    },
    {
      "id": "hesela-recovery",
      "title": "Hesela: Snapshots and backups: which failures can you recover from?",
      "url": "https://hesela.com/analyses/snapshot-backup-recovery-boundaries/",
      "accessed": "2026-10-15"
    }
  ]
}