{
  "slug": "smb-lease",
  "term": "SMB lease",
  "aliases": [
    "SMB caching lease"
  ],
  "definition": "An SMB lease is a server-granted arrangement that permits selected client-side read, write, or handle caching while coordinating access to a shared object.",
  "note": "Lease state can be shared by several opens using the same client lease identity. HANDLE caching permits delayed closes or deferred opens; it is not the durable-handle reconnect capability. Conflicting operations can trigger revocation of caching rights. [leasing] The lease-request LeaseDuration field is reserved, not an application-selectable expiry interval. [leasewire] Client caching rights describe buffering, not stable-write completion. [client] [write] Classic oplock levels have a different request form. [create] A lease can cache byte-range locks under WRITE caching, but a caching lease and a range lock serve different purposes. [client] Gray and Cheriton's historical time-bounded cache protocol is context, not the SMB wire contract or an expiry setting for this reserved field. [gray-cheriton] [leasewire]",
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "related": [
    "smb-protocol",
    "smb-durable-handle",
    "smb-persistent-handle",
    "smb-oplock",
    "smb-byte-range-lock"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "leasing",
      "title": "Microsoft MS-SMB2 section 3.3.1.4: Algorithm for Leasing in an Object Store",
      "url": "https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/d8df943d-6ad7-4b30-9f58-96ae90fc6204",
      "accessed": "2026-10-13"
    },
    {
      "id": "leasewire",
      "title": "Microsoft MS-SMB2 section 2.2.13.2.8: Lease request",
      "url": "https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/250a5100-f8b0-4b32-a202-f592ce4c05e7",
      "accessed": "2026-10-13"
    },
    {
      "id": "client",
      "title": "Microsoft MS-SMB2 section 3.2.1.5: Per Open File",
      "url": "https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/3538a6c5-25a1-41e3-ba35-de0e0633034b",
      "accessed": "2026-10-13"
    },
    {
      "id": "write",
      "title": "Microsoft MS-SMB2 section 2.2.21: SMB2 WRITE Request",
      "url": "https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/e7046961-3318-4350-be2a-a8d69bb59ce8",
      "accessed": "2026-10-13"
    },
    {
      "id": "create",
      "title": "Microsoft MS-SMB2 section 2.2.13: SMB2 CREATE Request",
      "url": "https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/e8fb45c1-a03d-44ca-b7ae-47385cfd7997",
      "accessed": "2026-10-14"
    },
    {
      "id": "gray-cheriton",
      "title": "Cary G. Gray and David R. Cheriton: Leases: An Efficient Fault-Tolerant Mechanism for Distributed File Cache Consistency (SOSP 1989), sections 2, 3.2 and 5",
      "url": "https://www.cs.cmu.edu/afs/cs.cmu.edu/academic/class/15712-s12/www/papers/gray89.pdf",
      "accessed": "2026-10-14"
    }
  ],
  "updated": "2026-10-14"
}