{
  "slug": "nvme-reclaim-unit-handle",
  "term": "NVMe reclaim unit handle",
  "aliases": [
    "FDP reclaim unit handle",
    "RUH"
  ],
  "definition": "An FDP controller resource that references one reclaim unit in each reclaim group of an endurance group.",
  "note": "A namespace-scoped placement handle maps to an endurance-group-scoped RUH. [base] A handle can switch to another RU when its current unit fills; it is not a permanent physical address. [overview] Initially Isolated and Persistently Isolated handle types have different rules for preserving segregation during controller relocation. [samsung]",
  "related": [
    "nvme-fdp",
    "nvme-reclaim-unit",
    "nvme-placement-identifier",
    "namespace-nvme"
  ],
  "advantages": [],
  "limitations": [
    {
      "text": "An RUH does not by itself promise permanent physical isolation from every other workload.",
      "citationIds": [
        "samsung"
      ]
    }
  ],
  "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": "overview",
      "title": "NVM Express. Flexible Data Placement Overview, FMS 2023, slides 6-7 and 16-23. Historical architecture overview, not a current software-support matrix.",
      "url": "https://nvmexpress.org/wp-content/uploads/FMS-2023-Flexible-Data-Placement-FDP-Overview.pdf",
      "accessed": "2026-10-12"
    },
    {
      "id": "samsung",
      "title": "Samsung. Getting Started with Flexible Data Placement, v4, sections 4.1.1 and 6.1. Vendor implementation guide.",
      "url": "https://download.semiconductor.samsung.com/resources/white-paper/getting-started-with-fdp-v4.pdf",
      "accessed": "2026-10-12"
    }
  ],
  "status": "limited",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}