{
  "slug": "nvme-command-quiesce-time",
  "term": "NVMe Command Quiesce Time",
  "aliases": [
    "Command Quiesce Time",
    "CQT"
  ],
  "definition": "NVMe Command Quiesce Time is an Identify Controller field reporting the expected worst-case time needed to quiesce outstanding commands after communication loss.",
  "note": "Base 2.3 defines CQT in Identify Controller bytes 387:386, in one-millisecond units. Zero means that the time is not reported, not that quiescence is instantaneous; a controller requiring no time should report one millisecond. [nvme-keep-alive-23]\n\nCommunication-loss detection and subsequent command quiescence are separate stages. CQT is not the Keep Alive Timeout, a per-command latency limit or the host's reconnection retry budget. Keep the timer's owner and starting event with any recorded value. [nvme-keep-alive-23]\n\nHesela's interpretation: stopping outstanding processing does not show that earlier effects were undone or that a write became durable. Retain command completion and recovery evidence rather than treating elapsed CQT as a successful write acknowledgment. [nvme-keep-alive-23]\n\nBase 2.3 section 9.6.2.1 separates detection from the additional quiescence wait. Its time-based detection paths use 2 * KATT after the last submitted Keep Alive command, or 3 * KATT after the last submitted command for traffic-based operation. These assume transport delay of at most one KATT, the controller's Keep Alive timeout interval. They are not unconditional failover deadlines. [nvme-keep-alive-23]",
  "related": [
    "nvme-keep-alive",
    "io-timeout",
    "nvme-abort"
  ],
  "limitations": [
    {
      "text": "An unreported CQT cannot be interpreted as a zero-duration quiescence guarantee.",
      "citationIds": [
        "nvme-keep-alive-23"
      ]
    }
  ],
  "citations": [
    {
      "id": "nvme-keep-alive-23",
      "title": "NVM Express Base 2.3 (2025): sections 3.9, 5.2.1.1 and 9.6.2.1; Figures 328 and 416, Keep Alive, KATO and Command Quiesce Time.",
      "url": "https://nvmexpress.org/wp-content/uploads/NVM-Express-Base-Specification-Revision-2.3-2025.08.01-Ratified.pdf",
      "accessed": "2026-11-08"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-08"
}