{
  "slug": "flashtier",
  "term": "FlashTier",
  "aliases": [],
  "definition": "FlashTier is a research storage-cache architecture that couples a cache-specific flash interface with host cache management.",
  "note": "The SSC uses backing-disk logical addresses. Silent eviction can discard clean cached data instead of relocating it during collection; dirty data must remain protected. A later miss may require a backing-disk read. [flashtier2012]\n\nThe 2012 evaluation uses simulation and emulation. The 2013 OpenSSD prototype changes mapping and persistence mechanisms, so its guarantees are not interchangeable with the original design. [flashtier2012] [flashtier2013]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "The hardware prototype checkpoints on ATA flush; inaccessible spare-area storage forced a different metadata log. These are historical research implementations, not a standard SSD capability.",
      "citationIds": [
        "flashtier2013"
      ]
    }
  ],
  "related": [
    "garbage-collection",
    "write-back-cache"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "flashtier2012",
      "title": "Saxena, Swift and Zhang. FlashTier: A Lightweight, Consistent and Durable Storage Cache. EuroSys 2012, pp. 267-280; sections 3.1-3.4, 4.3 and 6.1.",
      "url": "https://research.cs.wisc.edu/sonar/projects/FlashTier/eurosys12_flashtier.pdf",
      "accessed": "2026-11-14"
    },
    {
      "id": "flashtier2013",
      "title": "Saxena et al. Getting Real: Lessons in Transitioning Research Simulations into Hardware Systems. FAST 2013, pp. 215-228; sections 3.2.2 and 3.3.2.",
      "url": "https://www.usenix.org/system/files/conference/fast13/fast13-final42.pdf",
      "accessed": "2026-11-14"
    },
    {
      "id": "hesela",
      "title": "Hesela: NAND erase blocks and the FlashTier cache exception",
      "url": "https://hesela.com/analyses/nand-erase-block-size-gc-cost/#flashtier",
      "accessed": "2026-11-14"
    }
  ],
  "updated": "2026-11-14",
  "provenance": [
    "Primary-source synthesis; no FlashTier simulator, hardware benchmark or power-loss experiment reproduced."
  ]
}