Seagate is faced with a class-action lawsuit from customers who purchased the company's ST3000DM001 terabyte hard drives. Nearly a year ago, Blackblaze, a cloud backup service provider, decided to discontinue using Seagate's 3 TB drives after it was found that they have very high failure rates.

The service provider presented proof of this fact by comparing the 2015 performances of Seagate vs Western Digital as well as other brands of hard drives. Whereas other brands have failure rates ranging from only 4 to 8 percent, hard drives made by Seagate has a troublesome 32 percent.

Failure rates are not only high, but they are also distributed in varied ways. In normal hard drive performance, there is what is called the 'bathtub curve' failure rate. A period of high failure is expected at the start of operation as defective units die. This is followed by a lower failure rate until the units' end-of-life simply because old units burn out.

But hard drives produced by Seagate and used by Backblaze did not manifest this curve. By April 2015, only about 6 percent of the 3TB HDs that the cloud service provider bought from the hard drive maker were left operating.

The class-action lawsuit also charged that the hard drive manufacturer made false claims about the dependability and reliability in the promotion of its disk storage products. It cited the data compiled by the cloud service provider.

The Seagate vs Western Digital issue becomes even more significant if the data is closely examined. All 3TB drives made by Seagate are three times more likely to fail than the 3TBs made by Western Digital. The hard drives are also ten times more likely to fail as those made by Hitachi.

The complaint also noted that the ST3000DM001 was the only 3TB hard drive that uses three platters at one TB each. Other hard drive makers of 3TBs use four to five platters to achieve the 3T densities.