{
  "slug": "nvme-reclaim-unit",
  "term": "NVMe reclaim unit",
  "aliases": [
    "FDP reclaim unit",
    "RU (FDP)"
  ],
  "definition": "An FDP storage abstraction within a reclaim group that the controller can physically erase independently of other reclaim units.",
  "note": "A reclaim group contains reclaim units; an RU is not a host logical-address interval or a ZNS zone. [base] In NVM Command Set 1.1, RUAMW reports the currently writable logical-block count. After conversion using the namespace's formatted LBA size, the amount may be smaller or larger than the Reclaim Unit Nominal Size. [nvm]",
  "related": [
    "nvme-fdp",
    "nvme-reclaim-unit-handle",
    "nvme-placement-identifier",
    "garbage-collection",
    "zns"
  ],
  "advantages": [],
  "limitations": [
    {
      "text": "Do not substitute a nominal RU size for the currently reported remaining write capacity.",
      "citationIds": [
        "nvm"
      ]
    }
  ],
  "citations": [
    {
      "id": "base",
      "title": "NVM Express Base Specification 2.1 (5 August 2024), sections 1.5.73-74 and 1.5.82-84: FDP terminology.",
      "url": "https://nvmexpress.org/wp-content/uploads/NVM-Express-Base-Specification-Revision-2.1-2024.08.05-Ratified.pdf",
      "accessed": "2026-10-12"
    },
    {
      "id": "nvm",
      "title": "NVM Express NVM Command Set Specification 1.1 (5 August 2024), section 3.2.1.1 Figure 20 and section 4.1.6 Figure 125.",
      "url": "https://nvmexpress.org/wp-content/uploads/NVM-Express-NVM-Command-Set-Specification-Revision-1.1-2024.08.05-Ratified.pdf",
      "accessed": "2026-10-12"
    }
  ],
  "status": "limited",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}