{
  "slug": "nova",
  "term": "NOVA file system",
  "aliases": [
    "NOVA",
    "NOn-Volatile memory Accelerated file system"
  ],
  "definition": "NOVA is a research file system for hybrid DRAM and nonvolatile main memory that maintains a separate persistent log per inode.",
  "note": "The FAST 2016 design keeps file data outside per-inode logs and reconstructs DRAM indexes from persistent metadata. Multi-inode operations use lightweight journaling. Its atomic-mmap maps replica pages and commits them through msync; it is not DAX-mmap. [nova-paper]\n\nThe later NOVA-Fortis design adds corruption protection but exempts read/write DAX-mapped pages from its always-current checksum/parity guarantee. [fortis-paper]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "These are historical research designs, not guarantees for every persistent-memory filesystem or current Linux build.",
      "citationIds": [
        "nova-paper",
        "fortis-paper"
      ]
    }
  ],
  "related": [
    "persistent-memory",
    "dax",
    "crash-consistency",
    "persistence-ordering"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-13",
  "citations": [
    {
      "id": "nova-paper",
      "title": "Jian Xu and Steven Swanson. NOVA: A Log-structured File System for Hybrid Volatile/Non-volatile Main Memories. FAST 2016, pp. 323-338, sections 3 and 4.5-4.7.",
      "url": "https://cseweb.ucsd.edu/~swanson/papers/FAST2016NOVA.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "fortis-paper",
      "title": "Jian Xu, Lu Zhang et al. NOVA-Fortis: A Fault-Tolerant Non-Volatile Main Memory File System. SOSP 2017, sections 1 and 4.2-4.3. DOI: 10.1145/3132747.3132761.",
      "url": "https://cseweb.ucsd.edu/~swanson/papers/SOSP2017-NOVAFortis.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "hesela-pmem",
      "title": "Hesela: NOVA recovery and mapped-data protection.",
      "url": "https://hesela.com/analyses/pmem-persistence-domains-dax/#nova",
      "accessed": "2026-11-13"
    }
  ],
  "provenance": [
    "Primary-source comparison; no prototype execution, power-loss experiment or benchmark replication. See FAST 2016 section 4.5 and SOSP 2017 section 4.3 for the distinct mapping contracts."
  ]
}