{
  "slug": "nvme-command-retry-delay",
  "term": "NVMe Command Retry Delay",
  "aliases": [
    "NVMe CRD",
    "Command Retry Delay"
  ],
  "definition": "NVMe Command Retry Delay is a two-bit completion-status selector for retry timing when advanced command retry is enabled and Do Not Retry is clear.",
  "note": "Conditions: CRD is reserved if DNR=1 or Host Behavior Support ACRE=0. With DNR=0 and ACRE=1, 00b allows immediate retry; 01b, 10b and 11b select Identify Controller CRDT1, CRDT2 and CRDT3, each in 100 ms units. CRD is a selector, not a duration. [base23-retry]\n\nTiming: The host should wait the selected interval, but an earlier retry is not a protocol error. This is not a completion deadline or a recovery guarantee. [base23-retry]\n\nImplementation: Linux v6.12 nvme_retry_req indexes the selected CRDT value, multiplies it by 100 and requeues the request with a delay. This versioned function illustrates timing after a retry decision; it does not describe every host's retry policy. [linux-retry]",
  "related": [
    "nvme",
    "nvme-completion-queue",
    "nvme-do-not-retry",
    "nvme-error-information-log",
    "io-timeout",
    "retry-budget"
  ],
  "citations": [
    {
      "id": "base23-retry",
      "title": "NVM Express Base 2.3, section 4.2.3, Figure 100 and Identify Controller Figure 328: DNR, CRD and CRDT1-3",
      "url": "https://nvmexpress.org/wp-content/uploads/NVM-Express-Base-Specification-Revision-2.3-2025.08.01-Ratified.pdf",
      "accessed": "2026-10-23"
    },
    {
      "id": "linux-retry",
      "title": "Linux v6.12, nvme_retry_req: CRD selection, 100 ms conversion and requeue",
      "url": "https://github.com/torvalds/linux/blob/v6.12/drivers/nvme/host/core.c#L317-L330",
      "accessed": "2026-10-23"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-23",
  "provenance": [
    "Based on Base 2.3 and a pinned Linux function; no host/device execution, latency measurement or success-rate claim."
  ]
}