{
  "slug": "fastcdc",
  "term": "FastCDC",
  "aliases": [
    "Fast Content-Defined Chunking"
  ],
  "definition": "FastCDC is a content-defined chunking approach that combines Gear-based boundary selection, sub-minimum skipping and chunk-size normalization.",
  "note": "The 2016 design changes boundary-test strictness before and after a target length. Normalization narrows the size distribution rather than making chunks fixed-sized; reported speedups apply to the paper's implementations and workloads, not every backup system. [fastcdc]",
  "related": [
    "content-defined-chunking",
    "rolling-hash",
    "deduplication"
  ],
  "citations": [
    {
      "id": "fastcdc",
      "title": "Wen Xia, Yukun Zhou, Hong Jiang, Dan Feng, Yu Hua, Yuchong Hu, Yucheng Zhang and Qing Liu. FastCDC: A Fast and Efficient Content-Defined Chunking Approach for Data Deduplication. USENIX ATC 2016, pp. 101-114, sections 4-5.",
      "url": "https://www.usenix.org/system/files/conference/atc16/atc16-paper-xia.pdf",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela-cdc",
      "title": "Content-defined chunking: boundaries are not identity",
      "url": "https://hesela.com/analyses/content-defined-chunking-boundaries/",
      "accessed": "2026-10-12"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}