Backup and cloud storage supplier Backblaze has released its quarterly disk drive stats report.
The company had 301,120 hard drives used to store data as of the end of last year. A chart of the Q4 2024 disk drive annual failure rates (AFR) for various suppliers’ drive types shows a pronounced 4.5-plus percent AFR for four drives. These outliers were a 12 TB HGST model (HUH7212ALN604) and three Seagate drives with 10 (ST10000NM0086), 12 (ST12000NM0007), and 14 TB (ST14000NM0138) capacities:
The average AFR across all the drives was 1.35 percent.
There were positive outliers as well, with five drive models having zero failures for the quarter: a 4 TB HGST (HMS5C4040ALE640), Seagate 8 TB (ST8000NM000A), 14 TB (ST14000NM000J), 16 TB (ST16000NM002J), and 24 TB (ST24000NM002H). Blogger Andy Klein says: “The 24 TB Seagate drives join the 20 TB Toshiba and 22 TB WDC drive models in the 20-plus club as we continue to dramatically increase storage capacity while optimizing existing storage server space.”
Backblaze also presents full 2024 year AFR numbers, which we have charted as well:
Seagate’s 12 TB (ST12000NM0007) drive has by far the worst AFR in both the Q4 and full 2024 year stats, with its 14 TB (ST14000NM0138) and 10 TB (ST10000NM0086) models as well as HGST’s 12 TB (HUH7212ALN604) faring badly in the full-year AFR table.
Klein writes: “There were no qualifying drive models with zero failures in 2024. That said, the 16 TB Seagate model (ST16000NM002J) got close by recording just one drive failure back in Q3, giving the drive an AFR of 0.22 percent for 2024.” The average full 2024 AFR was 1.57 percent, better than 2023’s 1.7 percent. Klein expects the 2025 AFR to be lower still.
Backblaze installed 53,337 drives in the year, averaging 26 drives per hour per technician. It tracked AFR by drive size over the past few quarters:
The 10 TB drives have the highest AFR rating, followed by 12 TB ones in 2024 and the 8 TB drives. Klein says: “The 8 TB (gray line) drives and 12 TB (purple line) drives range in age from five to eight years, and as such their overall failure rates should be increasing over time.”
“The 14 TB (green line) and 16 TB (azure line) drives comprise 57 percent of the drives in service and on average they range in age from two to four years. They are in the prime of their working lives. As such, they should have low and stable failure rates, and as you can see, they do.”
Klein cuts the numbers another way to reveal AFRs by supplier:
HGST has climbed to the top of this particular tree in 2024, delivering poorer AFR rates than the previous worst supplier, Seagate, with Toshiba second best and Western Digital providing the most reliable drives of all. HGST’s lousy result is due to its 12 TB drives. Remove them from the equation, and the 2024 AFR for HGST drives would be 0.55 percent.
Klein is now retiring after several years of presenting these illuminating HDD failure rate stats, which are not available anywhere else. He deserves a terrific vote of thanks for this service.
The complete dataset used to create the tables and charts in this report is available on Backblaze’s Hard Drive Test Data page. You can download and use this data for free for your own purposes, but must cite Backblaze as the source.
