{
  "slug": "wsbuffer",
  "term": "WSBuffer",
  "aliases": [
    "Write-scrap buffering"
  ],
  "definition": "WSBuffer is a research I/O architecture that separates partial-write buffering from read caching and sends large aligned write regions directly to SSDs.",
  "note": "Its scrap buffer tracks valid byte ranges; a two-stage flusher fills missing data before writing complete regions. Only still-unfilled pages need a fill read; intervening writes can complete a page and bypass that read. The large-write alignment unit is the scrap-page data zone, not an application's direct-I/O alignment. [wsbuffer-paper]\n\nThe prototype modifies XFS on Linux 6.8. Evaluation used eight PCIe 4.0 SSDs in RAID0; ScaleCache comparisons used Linux 5.4. These are configuration-specific experiments, not a matched-kernel universal ranking. [wsbuffer-paper]\n\nThe flusher's Bcount tracks outstanding write bytes, not a measured latency or bandwidth rate; the paper uses it as a coarse busyness signal. [wsbuffer-paper]",
  "related": [
    "buffered-io",
    "direct-io",
    "page-cache",
    "fsync"
  ],
  "status": "research",
  "advantages": [
    {
      "text": "Targets partial-write overhead while retaining read caching and the buffered application interface.",
      "citationIds": [
        "wsbuffer-paper"
      ]
    }
  ],
  "limitations": [
    {
      "text": "Porting requires filesystem integration; the paper delegates durability and crash consistency to the underlying filesystem.",
      "citationIds": [
        "wsbuffer-paper"
      ]
    }
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-05",
  "citations": [
    {
      "id": "wsbuffer-paper",
      "label": "Zhan et al., FAST 2026",
      "title": "Zhan et al. Rearchitecting Buffered I/O in the Era of High-Bandwidth SSDs. FAST 2026, pp. 579-595; sections 3-4.",
      "url": "https://www.usenix.org/system/files/fast26-zhan.pdf",
      "accessed": "2026-11-05"
    }
  ],
  "provenance": [
    "Source-reviewed research identity, not a shipping-kernel support assertion or an independent benchmark.",
    "The evaluation's SSD model is Samsung 990 PRO; no independent prototype reproduction was performed. [wsbuffer-paper]"
  ]
}