{
  "slug": "sas-zoning",
  "term": "SAS zoning",
  "aliases": [
    "SAS-2 zoning",
    "PHY-based SAS zoning"
  ],
  "definition": "SAS zoning controls which groups of expander PHYs may communicate by applying configured access permissions.",
  "note": "In PHY-resolved zoning, expander PHYs belong to zone groups whose permission table controls communication. Hosts sharing a SAS domain need not have access to the same storage. [oracle-zoning]\n\nZoning, table-to-table routing and self-configuration are separate capabilities. Reachability alone does not establish access policy, encryption or independent failure paths. [microchip-expander] [oracle-zoning]\n\nThe smp_discover documentation explains that zoning-hidden PHYs can appear as 'phy vacant'; --ignore sets the request's Ignore Zone Group bit. A broader management view is not an access grant for ordinary I/O. Record initiator identity and request options when comparing inventories. [smp-discover]\n\nA 2008 domain-management proposal distinguishes ordinary I/O, zone management and domain management. These roles can differ even for the same initiator. [t10-zone-roles]\n\nIn the storage-module configuration documented by the cited service manual, moving the module to a different chassis slot erases saved expander zoning assignments. That maintenance constraint is product-specific: follow the enclosure's recovery procedure before diagnosing a failed drive. Do not disable zoning as a generic discovery fix. [oracle-zoning]",
  "status": "shipping",
  "advantages": [
    {
      "text": "Can assign storage access to selected hosts within a shared SAS fabric.",
      "citationIds": [
        "oracle-zoning"
      ]
    }
  ],
  "limitations": [
    {
      "text": "The expander, management software and active configuration must support and enforce the intended policy.",
      "citationIds": [
        "microchip-expander"
      ]
    },
    {
      "text": "Access separation does not remove shared hardware failure domains.",
      "citationIds": [
        "oracle-zoning"
      ]
    }
  ],
  "related": [
    "sas",
    "sas-expander",
    "sas-phy",
    "serial-management-protocol",
    "initiator-target",
    "dual-port"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "microchip-expander",
      "title": "Microchip SXP 12 Gbps SAS Expander Family, DS00003036A (July 2019), pp. 1-2: table-to-table routing, zoning and address support",
      "url": "https://www.microchip.com/content/dam/mchp/documents/DCS/ProductDocuments/Brochures/00003036A.pdf",
      "accessed": "2026-10-20"
    },
    {
      "id": "oracle-zoning",
      "title": "Oracle Sun Blade Storage Module M2 Service Manual (January 2012), pp. 9-10 and 12: zoning, access permissions and dual paths",
      "url": "https://docs.oracle.com/cd/E19452-01/pdf/821-0912.pdf",
      "accessed": "2026-10-20"
    },
    {
      "id": "smp-discover",
      "title": "Oracle Solaris smp_discover(8), July 2022: --ignore and zoning-hidden PHYs",
      "url": "https://docs.oracle.com/cd/E88353_01/html/E72487/smp-discover-8.html",
      "accessed": "2026-10-21"
    },
    {
      "id": "t10-zone-roles",
      "title": "Brad Besmer, T10/08-267r1 file: SAS-2 Domain Management Zoning Interaction, 14 July 2008, Overview p. 1",
      "url": "https://www.t10.org/ftp/t10/document.08/08-267r1.pdf",
      "accessed": "2026-10-21"
    }
  ],
  "provenance": [
    "The implementation examples are Oracle Sun Blade Storage Module M2 and Microchip SXP 12G. No universal zone-count limit, current product survey or penetration test is claimed.",
    "Encryption and redundancy distinctions are engineering consequences of connection-permission control, not measured guarantees.",
    "SAS access zoning is distinct from zoned block storage, where zones describe media address ranges and write rules.",
    "The T10 URL ends in 08-267r1.pdf but its internal header says Revision 0; the cited overview is dated 14 July 2008. No experiment on a SAS fabric or access-control bypass was performed.",
    "The slot-relocation constraint applies to Oracle Sun Blade Storage Module M2, January 2012 manual pp. 18-19; it is not a universal behavior of SAS shelves."
  ],
  "updated": "2026-10-21"
}