{
  "slug": "memory-persistency",
  "term": "Memory persistency",
  "aliases": [
    "memory persistency model"
  ],
  "definition": "Memory persistency specifies the permitted ordering of durable updates relative to other memory events and system failure.",
  "note": "The recovery observer captures surviving state; it is distinct from the observers used to reason about inter-thread visibility. A persistence domain describes protected components, whereas a persistency model describes ordering. [retrospective] Strict, epoch and strand models differ in which dependencies they preserve. They are not names for media types or blanket hardware guarantees. [pelley14]",
  "status": "research",
  "advantages": [],
  "limitations": [],
  "related": [
    "persistence-domain",
    "persistence-ordering",
    "persistent-memory",
    "strict-persistency",
    "epoch-persistency",
    "strand-persistency"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-19",
  "citations": [
    {
      "id": "pelley14",
      "title": "Pelley, Chen and Wenisch. Memory Persistency. ISCA 2014, pp. 265-276; sections 4-5 and 7-8, Table 1.",
      "url": "https://courses.grainger.illinois.edu/ece598ms/fa2019/papers/paper61.pdf",
      "accessed": "2026-10-19"
    },
    {
      "id": "han21",
      "title": "Han and Kimura. Durable Queue Implementations Built on a Formally Defined Strand Persistency Model. JIP 29 (2021), pp. 823-838, sections 2-3.",
      "url": "https://www.jstage.jst.go.jp/article/ipsjjip/29/0/29_823/_pdf/-char/en",
      "accessed": "2026-10-19"
    },
    {
      "id": "retrospective",
      "title": "Steven Pelley, Peter M. Chen and Thomas F. Wenisch. RETROSPECTIVE: Memory Persistency. ISCA retrospective, 2023; sections I-II.",
      "url": "https://bpb-us-w2.wpmucdn.com/sites.coecis.cornell.edu/dist/7/587/files/2023/06/Pelley_2014_Memory.pdf",
      "accessed": "2026-10-19"
    },
    {
      "id": "hesela-pmem",
      "title": "Hesela. Persistent memory: DAX is not a durable commit.",
      "url": "https://hesela.com/analyses/pmem-persistence-domains-dax/#persistency-models",
      "accessed": "2026-10-19"
    }
  ]
}