{
  "slug": "nvme-nsid",
  "term": "NVMe namespace ID (NSID)",
  "aliases": [
    "NSID",
    "NVMe namespace ID"
  ],
  "definition": "An NVMe namespace ID (NSID) is a 32-bit handle used by a controller and host to address a namespace, not a globally unique namespace identity.",
  "note": "Allocation describes whether a namespace exists; active status describes attachment to a particular controller [nvme-base-2-0e]. Base 2.3 requires subsystem-wide NSID uniqueness when Namespace Management, ANA Reporting, NVM Sets, or Sanitize Namespace is supported; otherwise, shared namespaces still require uniqueness but private namespaces need not [nvme-base-2-3]. Within one NVM subsystem, the same shared namespace uses the same NSID through its attached controllers [nvme-base-2-0e].\n\nNSIDs may change across power-off conditions; use supported namespace identifiers to check continuity [nvme-base-2-0e]. The companion analysis separates namespace recognition from ANA path selection [hesela-ana].",
  "status": "shipping",
  "advantages": [
    "Provides a compact command-level reference to a namespace."
  ],
  "limitations": [
    "An equal NSID on two unrelated subsystems does not establish that they expose the same namespace."
  ],
  "related": [
    "namespace-nvme",
    "nvm-subsystem",
    "nvme-namespace-identifiers",
    "nvme-subsystem-nqn",
    "multipath-nvme"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "nvme-base-2-0e",
      "title": "NVM Express Base Specification 2.0e, sections 2.4.1, 3.2.1 and 3.3.3.1; copyright 2008-2024 NVM Express, Inc., all rights reserved",
      "url": "https://nvmexpress.org/wp-content/uploads/NVM-Express-Base-Specification-2.0e-2024.07.29-Ratified.pdf",
      "accessed": "2026-10-16"
    },
    {
      "id": "nvme-base-2-3",
      "title": "NVM Express Base Specification 2.3, section 3.2.1.6; copyright 2008-2025 NVM Express, Inc., all rights reserved",
      "url": "https://nvmexpress.org/wp-content/uploads/NVM-Express-Base-Specification-Revision-2.3-2025.08.01-Ratified.pdf",
      "accessed": "2026-10-16"
    },
    {
      "id": "hesela-ana",
      "title": "NVMe multipath: ANA access states and Linux path policies",
      "url": "https://hesela.com/analyses/nvme-multipath-ana-path-selection/",
      "accessed": "2026-10-16"
    }
  ],
  "updated": "2026-10-16"
}