{
  "slug": "transparent-compression",
  "term": "Transparent filesystem compression",
  "aliases": [
    "Transparent compression"
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-16",
  "definition": "Filesystem-managed compression of eligible file data that preserves the original logical bytes exposed to applications.",
  "note": "In Btrfs, changing compression policy affects new writes, leaving existing data untouched. A defragmentation-selected algorithm applies to that operation, not all future writes. [btrfs-compression]\n\nAttempting compression is not a guarantee that each block is stored compressed: even compress-force may retain an uncompressed representation. [btrfs-compression]",
  "related": [
    "reflink",
    "filesystem-defragmentation",
    "copy-on-write",
    "file-extent"
  ],
  "citations": [
    {
      "id": "btrfs-compression",
      "title": "Btrfs-progs v6.16: Compression, new writes and operation-local policy",
      "url": "https://raw.githubusercontent.com/kdave/btrfs-progs/v6.16/Documentation/ch-compression.rst",
      "accessed": "2026-10-16"
    },
    {
      "id": "hesela-clones",
      "title": "Hesela: Fast file clones and deferred copying costs",
      "url": "https://hesela.com/analyses/file-clones-deferred-copy-cost/",
      "accessed": "2026-10-16"
    }
  ],
  "provenance": [
    "The Btrfs-specific details use btrfs-progs v6.16 documentation; no compression ratio or performance measurement is claimed."
  ]
}