{
  "slug": "enterprise-ssd-replacements",
  "title": "Enterprise SSD replacements ran at 0.22% a year across 1.4 million NetApp drives, with firmware the biggest swing",
  "kind": "dataset",
  "summary": "Maneas et al., FAST 2020, mined NetApp support messages for about 1.4 million SSDs (3 manufacturers, 18 models, January 2017 to May 2019). The average annual replacement rate was 0.22%, from 0.07% to nearly 1.2% by model. Early firmware versions of some families were replaced 2 to more than 10 times as often as later ones, and the chance of another replacement within a week in a RAID group was 9.39% against 0.0504% in a random week. Cross-check rows come from Google (FAST 2016).",
  "license": "Small derived table of figures printed in Maneas et al. (FAST 2020) and Schroeder et al. (FAST 2016), with credit. Not a Creative Commons license. The USENIX proceedings state that rights to individual papers remain with the author or the author's employer. This file is not a copy of the papers and not the underlying telemetry.",
  "licenseUrl": "https://www.usenix.org/system/files/fast20-maneas.pdf",
  "sourceUrl": "https://www.usenix.org/system/files/fast20-maneas.pdf",
  "accessed": "2026-10-10",
  "rowCount": 17,
  "columns": [
    {
      "name": "measure",
      "type": "string",
      "description": "The quantity as the source names it."
    },
    {
      "name": "value_low",
      "type": "number",
      "description": "Lower end of a printed range. Empty when the source prints a single value."
    },
    {
      "name": "value_high",
      "type": "number",
      "description": "Single printed value, or the upper end of a range. For 'more than half' it is the stated bound."
    },
    {
      "name": "unit",
      "type": "string",
      "description": "Unit of the value columns: disks, blocks, files, percent of disks, percent of mismatches, or probability."
    },
    {
      "name": "scope",
      "type": "string",
      "description": "Population and window the value applies to."
    },
    {
      "name": "note",
      "type": "string",
      "description": "What the value is not, or the source wording behind it."
    },
    {
      "name": "citation_id",
      "type": "string",
      "description": "Id of the opened source in the citations list."
    }
  ],
  "downloadPath": "/data/datasets/enterprise-ssd-replacements.csv",
  "humanPage": "https://hesela.com/analyses/enterprise-ssd-replacements/",
  "limits": [
    "Replacement is an operator action and about a third of replacements are predictive, so the annual replacement rate is not a data-loss rate.",
    "The reason is missing for 40% of replacement events and the paper assumes the rest are spread in proportion.",
    "The firmware effect is within one family; the cause is an explanation in the paper, not a measurement.",
    "Rated life used is a truncated integer, so many drives show 0.",
    "The Google rows measure the share of drives removed in 4 years, not an annual rate, and cover another fleet."
  ],
  "citations": [
    {
      "id": "maneas-fast20-pdf",
      "title": "A Study of SSD Reliability in Large Scale Enterprise Storage Deployments, Maneas et al., FAST 2020 (USENIX PDF)",
      "url": "https://www.usenix.org/system/files/fast20-maneas.pdf",
      "accessed": "2026-10-10"
    },
    {
      "id": "schroeder-fast16-pdf",
      "title": "Flash Reliability in Production: The Expected and the Unexpected, Schroeder, Lagisetty, and Merchant, FAST 2016 (USENIX PDF)",
      "url": "https://www.usenix.org/system/files/conference/fast16/fast16-papers-schroeder.pdf",
      "accessed": "2026-10-10"
    }
  ]
}