{
  "slug": "scsi-device-identification",
  "term": "SCSI Device Identification",
  "aliases": [
    "Device Identification VPD page",
    "SCSI VPD 0x83",
    "VPD page 83h"
  ],
  "definition": "SCSI Device Identification is the INQUIRY VPD page 0x83 mechanism for reporting typed identifiers associated with a logical unit, target port or target device.",
  "note": "A page can contain several designators with different associations; preserve the association, identifier type, code set and value together. A target-port designator does not identify the addressed logical unit merely because it appears in the same response. [sdparm-vpd]\n\nThe SCSI reference distinguishes association 0 for the addressed device from associations 1 and 2 for the receiving port and containing target. It describes association-0 identification as consistent across other paths to that device. Vendor-specific type 0 is not guaranteed globally unique; do not infer uniqueness from the page number alone. [seagate-scsi]\n\nsystemd v257 scsi_id selects logical-unit-associated descriptors for the device identifier while handling target-port-group information separately. This is a version-specific selection policy, not a rule that the first descriptor is always the correct identifier. [systemd-scsi-id]\n\nIn systemd v257, a binary NAA designator is rendered in ID_SERIAL as the type digit 3 followed by the hexadecimal identifier. Thus 36... begins with a host-format prefix 3 and an NAA value starting 6; ID_SERIAL_SHORT omits that type prefix. This is a pinned implementation's representation, not a universal WWID format. [systemd-scsi-id] [systemd-scsi-export]\n\nRFC 8154 restricts pNFS SCSI volume identifiers to association 0 and four allowed designator types. Several descriptors may still share association, code set and type; clients must examine all descriptors for a match to the supplied code set, designator type and value. This is pNFS matching against a supplied identity, not scsi_id's selection of a preferred host identifier. [rfc8154-match]",
  "related": [
    "scsi-logical-unit",
    "scsi-unit-serial-number",
    "world-wide-name",
    "multipath-io"
  ],
  "citations": [
    {
      "id": "sdparm-vpd",
      "title": "Douglas Gilbert: sdparm 1.12 documentation, VPD pages and descriptor associations",
      "url": "https://doug-gilbert.github.io/sdparm.html",
      "accessed": "2026-11-03"
    },
    {
      "id": "seagate-scsi",
      "title": "Seagate SCSI Commands Reference Manual, 100293068 Rev. L (November 2020), sections 5.4.9 and 5.4.22",
      "url": "https://www.seagate.com/files/staticfiles/support/docs/manual/Interface%20manuals/100293068L.pdf",
      "accessed": "2026-11-03"
    },
    {
      "id": "systemd-scsi-id",
      "title": "systemd v257: scsi_serial.c, check_fill_0x83_id, do_scsi_page80_inquiry and scsi_get_serial",
      "url": "https://raw.githubusercontent.com/systemd/systemd/v257/src/udev/scsi_id/scsi_serial.c",
      "accessed": "2026-11-03"
    },
    {
      "id": "systemd-scsi-export",
      "title": "systemd v257: scsi_id.c, sanitized ID_SERIAL and ID_SERIAL_SHORT exports",
      "url": "https://raw.githubusercontent.com/systemd/systemd/v257/src/udev/scsi_id/scsi_id.c",
      "accessed": "2026-11-03"
    },
    {
      "id": "rfc8154-match",
      "title": "RFC 8154 (May 2017), section 2.3.1: pNFS SCSI volume identification and descriptor matching",
      "url": "https://www.rfc-editor.org/rfc/rfc8154.html#section-2.3.1",
      "accessed": "2026-11-03"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-03",
  "provenance": [
    "Primary documentation and pinned implementation review on 2026-11-03; no device interrogation, failover experiment or global-uniqueness measurement."
  ]
}