{
  "slug": "device-managed-smr",
  "term": "Device-managed SMR (DM-SMR)",
  "aliases": [
    "drive-managed SMR"
  ],
  "definition": "An SMR HDD that presents a conventional LBA interface while the firmware relocates writes across shingled bands.",
  "note": "Device-managed (drive-managed) SMR keeps shingled media behind a conventional LBA interface: firmware accepts random writes, buffers them (often using a CMR media cache), and relocates data into shingled bands during idle garbage collection. No ZAC/ZBC zone commands are exposed; Linux reports `queue/zoned` as `none`, same as CMR. There is no separate industry command-set standard for this model because it is intentionally backward-compatible. The cost is workload-dependent performance: sustained random writes without idle time can stall when the persistent cache fills and band rewrite cannot keep up. WD and others have documented DMSMR in consumer/NAS lines and advised CMR for heavy random-rewrite RAID use.",
  "status": "shipping",
  "advantages": [
    {
      "text": "Works with legacy software unaware of zoned semantics.",
      "citationIds": [
        "c1"
      ]
    }
  ],
  "limitations": [
    {
      "text": "Sustained random write can trigger internal garbage collection and latency spikes.",
      "citationIds": [
        "c1"
      ]
    }
  ],
  "related": [
    "smr",
    "hm-smr",
    "nearline-hdd"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "c1",
      "title": "Shingled magnetic recording",
      "url": "https://en.wikipedia.org/wiki/Shingled_magnetic_recording",
      "accessed": "2026-03-26"
    },
    {
      "id": "n2",
      "title": "Zoned Storage — SMR disk models (drive-managed vs zoned)",
      "url": "https://zonedstorage.io/docs/getting-started/smr-disk",
      "accessed": "2026-10-07"
    },
    {
      "id": "n3",
      "title": "Zoned Storage — SMR introduction (drive-managed model)",
      "url": "https://zonedstorage.io/docs/introduction/smr",
      "accessed": "2026-10-07"
    },
    {
      "id": "n4",
      "title": "Western Digital — WD Red SMR vs CMR NAS drive information",
      "url": "https://support-en.wd.com/app/answers/detailweb/a_id/29458",
      "accessed": "2026-10-07"
    }
  ]
}