Dataset · Q4 2025 · computed from raw Backblaze files

Power-on age of failed drives versus the fleet, Backblaze Q4 2025

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.

Download CSV35 rows · 9 columns · CSV

File /data/datasets/backblaze-q4-2025-drive-age-at-failure.csv · JSON metadata · Chart (SVG) · All datasets · AFR glossary entry

Population and method

Population: hard drives of 3 TB or more in Backblaze’s own data centers in the 92 daily files from October 1 to December 31, 2025, limited to models with more than 100 drives on December 31 and more than 10,000 drive days in the quarter, the report’s quarterly rule. That leaves 34 models with 334,392 drives on December 31, 30,534,025 drive days and 943 failures, a pooled AFR of 1.13%. A drive day is one daily row, and a failure is a row with failure = 1.

Age is the raw value of SMART attribute 9 (power-on hours) divided by 8,766 hours per year. For failed drives it is read on the failure day, for the fleet on December 31. 924 of the 943 failures have the value filled in. All numbers are computed here from the daily files, not copied from Backblaze’s tables. As a check, three AFRs that Backblaze printed in its Q4 2025 text (HGST HUH728080ALE600 10.29%, Seagate ST10000NM0086 5.23%, Toshiba MG08ACA16TEY 4.14%) are reproduced exactly by this file, and the build fails if they stop matching.

Chart

Counted here

Pooled over all 34 models, the median age of failed drives is 4.65 years and the fleet median is 3.38 years. The pooled medians mix models of very different ages and sizes, so the gap combines model mix with any age effect and cannot be read as either.
Within single models the picture differs. Of the 16 models with 20 or more aged failures, the failed-drive median is above the fleet median for 5 and below it for 11. The largest gap in either direction is 0.68 years.
The three highest AFRs among models with 1,000 or more drives are HGST HUH728080ALE600 (10.29%, fleet median 8.12 years); TOSHIBA MG08ACA16TEY (4.14%, fleet median 3.75 years); ST24000NM002H (3.51%, fleet median 0.71 years).

Limits

One operator’s fleet, one quarter. Association only: this does not say that age causes or does not cause failure.
A median age of failed drives close to the fleet median means failures in the quarter were spread across the model’s age range. It does not give a failure rate by age, which needs each drive’s age on every day and is not computed here.
Models with few failures have unstable medians. The chart shows only models with 20 or more aged failures, and the table shows the rest with their counts.
Power-on hours are a drive-reported counter. This file does not check them for resets or vendor-specific encodings, so a model with an odd value would show up here unflagged.
Backblaze reports analysing 337,192 hard drives for Q4 2025. This file counts 334,392 under the rule above. The gap is not resolved here. Model names are used as they appear in the files, so WUH721816ALE6L4 appears twice, once with a WDC prefix, as they appear in the daily files.

Model table

Same 35 rows as the CSV, last row pooled. Sorted by December 31 drive count.
Model	TB	Drives Dec 31	Drive days	Failures	AFR (%)	Failures with age	Fleet median age (y)	Failed median age (y)
WDC WUH722222ALE6L4	22	44,265	3,945,245	25	0.23	25	1.17	0.65
TOSHIBA MG08ACA16TA	16	39,442	3,670,933	68	0.68	68	2.36	2.34
TOSHIBA MG07ACA14TA	14	37,213	3,428,534	76	0.81	76	5.13	5.81
ST16000NM001G	16	34,305	3,149,031	35	0.41	32	3.69	4.26
WDC WUH721816ALE6L4	16	26,310	2,421,840	44	0.66	44	2.89	3.19
ST12000NM0008	12	18,551	1,715,709	112	2.38	111	5.73	5.67
TOSHIBA MG10ACA20TE	20	17,999	1,656,127	28	0.62	28	0.77	1.06
ST8000NM0055	8	13,185	1,217,828	56	1.68	55	8.47	8.27
ST12000NM001G	12	13,147	1,214,910	31	0.93	30	5.06	5.12
HGST HUH721212ALE604	12	13,095	1,221,499	85	2.54	84	4.71	4.60
ST14000NM001G	14	10,464	968,495	34	1.28	34	5.13	5.00
HGST HUH721212ALN604	12	9,692	900,963	76	3.08	76	6.70	6.54
ST8000DM002	8	8,796	818,034	38	1.70	35	0.50	0.35
WDC WUH721414ALE6L4	14	8,630	794,489	14	0.64	14	5.06	4.89
ST24000NM002H	24	8,328	676,414	65	3.51	56	0.71	0.66
TOSHIBA MG08ACA16TE	16	6,210	568,599	9	0.58	9	4.22	4.03
TOSHIBA MG08ACA16TEY	16	4,861	449,560	51	4.14	51	3.75	3.40
TOSHIBA MG11ACA24TE	24	4,739	349,939	7	0.73	7	0.27	0.16
WDC WUH721816ALE6L0	16	2,979	274,524	11	1.46	11	4.12	3.89
HGST HUH721212ALE600	12	2,606	239,745	4	0.61	4	6.53	5.90
ST14000NM0138	14	1,251	115,388	10	3.16	10	5.04	4.88
WDC WUH722626ALE6L4	26	1,200	91,690	1	0.40	1	0.22	0.01
ST12000NM000J	12	1,059	96,136	1	0.38	1	1.44	1.96
HGST HUH728080ALE600	8	1,021	95,800	27	10.29	27	8.12	7.96
TOSHIBA MG07ACA14TEY	14	983	89,854	6	2.44	6	3.39	1.02
ST12000NM0007	12	981	90,539	9	3.63	9	6.28	6.06
ST10000NM0086	10	978	90,651	13	5.23	13	8.28	8.11
ST16000NM002J	16	465	42,714	0	0.00	0	3.55
ST14000NM000J	14	407	36,688	2	1.99	2	1.16	1.32
TOSHIBA MG09ACA16TE	16	348	28,207	2	2.59	2	0.46	0.54
WUH721816ALE6L4	16	340	24,001	1	1.52	1	1.13	0.96
ST8000NM000A	8	245	22,700	0	0.00	0	2.67
HGST HMS5C4040BLE640	4	186	17,151	1	2.13	1	8.78	8.85
ST16000NM000J	16	111	10,088	1	3.62	1	1.48	0.19
ALL 34 MODELS		334,392	30,534,025	943	1.13	924	3.38	4.65

Columns

model (string): Drive model string as it appears in the daily files. The last row is the pooled row for all included models.
size_tb (integer): Largest capacity_bytes seen for the model, in terabytes (10^12 bytes), rounded. Empty on the pooled row.
drives_2025_12_31 (integer): Rows for the model in the 2025-12-31 daily file, the quarter-end drive count.
drive_days (integer): Daily rows for the model from 2025-10-01 to 2025-12-31.
failures (integer): Rows with failure = 1 in that period.
afr_percent (number): failures / drive_days * 365 * 100, two decimals. Computed here from the daily files.
failures_with_age (integer): Failed drives whose smart_9_raw (power-on hours) was filled in on the failure day. Always at most failures.
fleet_median_age_years (number): Median smart_9_raw on 2025-12-31 over the model's drives, divided by 8766 hours per year.
failed_median_age_years (number): Median smart_9_raw of the failed drives on their failure day, divided by 8766. Empty when no failed drive has the value.

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.

Backblaze Drive Stats use terms · Hard Drive Test Data page

Sources

Backblaze Hard Drive Test Data, data_Q4_2025.zip (daily files, 92 CSVs) (accessed 2026-10-10)
Hard Drive Reliability & Test Data (accessed 2026-10-10)
Backblaze Drive Stats for 2025 (published Q4 2025 AFRs used as a cross-check) (accessed 2026-10-10)