Saturday, August 15, 2015

Failure rates among consumer-class hard drives

Read this before you buy another hard drive. Lucas Mearian. Computerworld. January 2014 and updated September, 2014.   
     An article looking at Backblaze, a data storage service provider, who detailed the failure rates among the more than 27,000 consumer-class hard drives it uses in its data center. The data center contains Seagate, Hitachi and Western Digital drives, plus some others that they mention. They have specific information which shows that in a three-year period, 3.1% of  the 12,956 Hitachi drives failed; 5.2% of 2,838 Western Digital drives failed; and a sizable 26.5% of the 12,765 Seagate drives failed. They had a small number of Toshiba and Samsung drives. They buy the least expensive drives available.

"Hitachi does really well. There is an initial die-off of Western Digital drives, and then they are nice and stable. The Seagate drives start strong, but die off at a consistently higher rate, with a burst of deaths near the 20-month mark." The study includes data on 15 drive models totaling more than 12,000 drives each from Seagate and Hitachi, and almost 3,000 drives from Western Digital. There were also several dozen drives from both Toshiba and Samsung, but not enough for solid statistical results.

In an updated post on the Backblaze blog they report they have 34,881 drives and store over 100 petabytes of data. They also report "The surprising (and bad) news is that Seagate 3.0TB drives are failing a lot more, with their failure rate jumping from 9% to 15%. The Western Digital 3TB drives have also failed more, with their rate going up from 4% to 7%."
As shown in the chart on the blog, the HGST (formerly Hitachi) drives have the lowest failure rate of all.

The question was asked if they were going to switch to enterprise drives. "The assumption that “enterprise” drives would work better than “consumer” drives has not been true in our tests. I analyzed both of these types of drives in our system and found that their failure rates in our environment were very similar — with the “consumer” drives actually being slightly more reliable."

No comments: