HDD reliability backblaze report: statistics from 2013 to 2017

The company Backblaze since 2013 keeps statistics on the operation of hard drives in its data centers. Specialists monitor which drives work without failures and failures for how long. There is also an analysis of the reliability of HDD from different manufacturers. The database includes the production date of the disc, manufacturer, model, serial number, status (whether the disk is working or dead), as well as SMART attributes that are reported by the disc itself. By the end of 2017, about 88 million objects had accumulated in the database. The size of the database is 23 GB. You can download it from the company's website - right here .

The new report indicates the data on the operation of HDD for 2017. At the time of drawing up the document, 91,305 hard drives were operating in the data centers of the company. The report can be viewed for different periods of time, including each quarter separately or information for the whole year.

At the end of the fourth quarter of 2017, the company monitored 91,305 disks. To improve the accuracy of the report, information about test models of hard drives was deleted, and models that the company has less than 45 copies are also not taken into account. As a result, 91,243 disks remained.



The company gives several explanations on the table:

• The percentage of failures is given only for the fourth quarter of last year. If any HDD model has a 0% failure rate, this means that there were no problems with disks in the fourth quarter;
• As mentioned above, 62 discs are not counted, since the number of models is too small to get any reliable statistics;
• Quarter failure rates may differ, especially for those models whose number is not too large, or they are used relatively shortly. For example, for Seagate 4 TB, the ST4000DM005 model has a failure rate of 29.08%. But this does not mean that disks of this type are extremely unreliable. They are simply not enough in the company, the data are based on 1255 disco days and only 1 refusal.

In 2017, the company added many new models of hard drives, replacing with a larger volume of 8, 10 and 12 TB of a smaller model - 2.3 and 4 TB. These changes are displayed in the diagram below.



Total added 25,746 new drives. 6442 disks were taken out of operation. As a result, the volume of the file space increased by 211 petabytes (HDD totaling 230 petabytes added and 10 petabyte drives removed).

Below is the full statistics for HDD, which remained in working condition at the time of the fourth quarter of 2017.



And now - a comparative table demonstrating the various characteristics of the HDD. For most, the story began in 2015, although there are newer models that began to work in 2017.



The percentage of failures was calculated for each year separately. In general, the conclusions can be drawn as follows:

• The percentage of failures for 6 TB models, manufacturers of Seagate and WDC fell over time. Many HDDs continue to work without any problems;
• Despite the fact that the percentage of failures of three-byte bytes from WDC seems to have also decreased, this is primarily due to the fact that about 1,000 such hard drives were decommissioned in 2017. This was done to replace them with more capacious ones. At the moment, only 180 such models remain in service;
• Toshiba 5 TB and HGST 8 TB have zero bounce rate last year. This is impressive, but the fact is that there are only 45 disks of each model in the system, which makes it impossible to get more accurate statistics;
• But the HGST / Hitachi 4 TB model has a failure rate of about 1% for three years. It is very impressive.

In the entire monitoring history, the company had 116,833 hard disks. At present, 91,305 disks are in operation, and 25,528 were either decommissioned for replacement or failed. In 2017, the company installed 29,844 new HDDs. According to representatives of the company, its statistics helps to understand which hard drive models of which manufacturers are more reliable than the rest, and they can be trusted. The reliability of the hard drive - a very important factor for data centers of any company. With the loss of HDD, especially several, you can lose the most important information, without which the work will be much more complicated.