{
  "slug": "backblaze-q4-2025-drive-age-at-failure",
  "title": "Power-on age of failed drives versus the fleet, Backblaze Q4 2025",
  "kind": "dataset",
  "summary": "Per-model power-on age of the hard drives that failed in Backblaze's Q4 2025 (October 1 to December 31, 2025) against the age of the fleet on December 31, computed from Backblaze's raw daily Drive Stats files. Sample: 34 hard-drive models, 334,392 drives on December 31, 30,534,025 drive days, 943 failures (1.13% pooled AFR), of which 924 carry a power-on-hours value. Pooled medians are 4.65 years for failed drives and 3.38 years for the fleet, but within single models the two medians are close.",
  "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 35-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": 35,
  "columns": [
    {
      "name": "model",
      "type": "string",
      "description": "Drive model string as it appears in the daily files. The last row is the pooled row for all included models."
    },
    {
      "name": "size_tb",
      "type": "integer",
      "description": "Largest capacity_bytes seen for the model, in terabytes (10^12 bytes), rounded. Empty on the pooled row."
    },
    {
      "name": "drives_2025_12_31",
      "type": "integer",
      "description": "Rows for the model in the 2025-12-31 daily file, the quarter-end drive count."
    },
    {
      "name": "drive_days",
      "type": "integer",
      "description": "Daily rows for the model from 2025-10-01 to 2025-12-31."
    },
    {
      "name": "failures",
      "type": "integer",
      "description": "Rows with failure = 1 in that period."
    },
    {
      "name": "afr_percent",
      "type": "number",
      "description": "failures / drive_days * 365 * 100, two decimals. Computed here from the daily files."
    },
    {
      "name": "failures_with_age",
      "type": "integer",
      "description": "Failed drives whose smart_9_raw (power-on hours) was filled in on the failure day. Always at most failures."
    },
    {
      "name": "fleet_median_age_years",
      "type": "number",
      "description": "Median smart_9_raw on 2025-12-31 over the model's drives, divided by 8766 hours per year."
    },
    {
      "name": "failed_median_age_years",
      "type": "number",
      "description": "Median smart_9_raw of the failed drives on their failure day, divided by 8766. Empty when no failed drive has the value."
    }
  ],
  "downloadPath": "/data/datasets/backblaze-q4-2025-drive-age-at-failure.csv",
  "chartPath": "/data/datasets/backblaze-q4-2025-drive-age-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": "bb-2025",
      "title": "Backblaze Drive Stats for 2025 (published Q4 2025 AFRs used as a cross-check)",
      "url": "https://www.backblaze.com/blog/backblaze-drive-stats-for-2025/",
      "accessed": "2026-10-10"
    }
  ]
}