{
  "slug": "backblaze-q4-2025-smart-at-failure",
  "title": "SMART 5, 187, 188, 197 and 198 in failed versus surviving drives, Backblaze Q4 2025",
  "kind": "dataset",
  "summary": "Share of drives with a non-zero raw value for five SMART attributes (5, 187, 188, 197, 198), computed from Backblaze's raw daily Drive Stats files for Q4 2025 (October 1 to December 31, 2025). Sample: 945 hard drives of 3 TB or more that failed in the quarter, read on their failure day, against 334,842 drives that survived to December 31. At least one of the five is above zero for 74.5% of failed drives that report any (690 of 926) and 8.1% of survivors. Association at the failure day, not a prediction test; one fleet, one quarter.",
  "license": "Derivative table computed from the Backblaze Drive Stats daily files for Q4 2025. Cite Backblaze if you use it. You are solely responsible for how you use it. Backblaze's dataset page allows sale of derivative works and forbids selling the Drive Stats data itself. This CSV is a 24-row aggregate, not the daily SMART archive, and that archive is not for sale.",
  "licenseUrl": "https://www.backblaze.com/cloud-storage/resources/hard-drive-test-data",
  "sourceUrl": "https://www.backblaze.com/cloud-storage/resources/hard-drive-test-data",
  "accessed": "2026-10-10",
  "rowCount": 24,
  "columns": [
    {
      "name": "manufacturer",
      "type": "string",
      "description": "All, or the manufacturer group inferred from the model string: Seagate (ST...), HGST (HGST, HUH, HMS), Toshiba, WDC (WDC, WUH, WD)."
    },
    {
      "name": "attribute",
      "type": "string",
      "description": "smart_5_raw (reallocated sectors), smart_187_raw (reported uncorrectable errors), smart_188_raw (command timeout), smart_197_raw (current pending sectors), smart_198_raw (offline uncorrectable), or any_of_five (at least one of the five above zero)."
    },
    {
      "name": "failed_drives",
      "type": "integer",
      "description": "Drives that failed between 2025-10-01 and 2025-12-31, one failure-day row each, hard drives of 3 TB or more."
    },
    {
      "name": "failed_filled",
      "type": "integer",
      "description": "Failed drives whose row has the attribute filled in (not blank). For any_of_five, at least one of the five filled."
    },
    {
      "name": "failed_above_zero",
      "type": "integer",
      "description": "Failed drives with the raw value above zero."
    },
    {
      "name": "failed_percent",
      "type": "number",
      "description": "failed_above_zero / failed_filled * 100, one decimal. Computed here."
    },
    {
      "name": "failed_percent_low95",
      "type": "number",
      "description": "Lower bound of the 95% Wilson score interval for failed_percent. Computed here."
    },
    {
      "name": "failed_percent_high95",
      "type": "number",
      "description": "Upper bound of the same interval."
    },
    {
      "name": "survivor_drives",
      "type": "integer",
      "description": "Drives of 3 TB or more in the 2025-12-31 file with failure = 0."
    },
    {
      "name": "survivor_filled",
      "type": "integer",
      "description": "Survivors with the attribute filled in."
    },
    {
      "name": "survivor_above_zero",
      "type": "integer",
      "description": "Survivors with the raw value above zero."
    },
    {
      "name": "survivor_percent",
      "type": "number",
      "description": "survivor_above_zero / survivor_filled * 100, one decimal. Computed here."
    }
  ],
  "downloadPath": "/data/datasets/backblaze-q4-2025-smart-at-failure.csv",
  "chartPath": "/data/datasets/backblaze-q4-2025-smart-at-failure.svg",
  "citations": [
    {
      "id": "bb-data",
      "title": "Backblaze Hard Drive Test Data, data_Q4_2025.zip (daily files, 92 CSVs)",
      "url": "https://f001.backblazeb2.com/file/Backblaze-Hard-Drive-Data/data_Q4_2025.zip",
      "accessed": "2026-10-10"
    },
    {
      "id": "bb-page",
      "title": "Hard Drive Reliability & Test Data",
      "url": "https://www.backblaze.com/cloud-storage/resources/hard-drive-test-data",
      "accessed": "2026-10-10"
    },
    {
      "id": "wilson-1927",
      "title": "Wilson, E. B. (1927). Probable inference, the law of succession, and statistical inference. Journal of the American Statistical Association 22(158), 209-212",
      "url": "https://doi.org/10.1080/01621459.1927.10502953",
      "accessed": "2026-10-10"
    }
  ]
}