To perform the test, Backblaze deployed two "Storage Pods" (the term it uses for self-contained storage arrays), each with 45 drives from Seagate and WD. The Western Digital Storage Pod was designated UL796 and the Seagate Storage Pod was designated UL800. Each Pod was identical in design and configuration except for the hard drives used.
Backblaze currently receives 130TB of data from its customers to store each day. Data arrives in similarly sized encrypted blocks. On any given day, 20 to 40 Storage Pods accept these data blocks as they arrive. As a block arrives, it is passed to a Storage Pod; if that Pod is busy, the data block is passed to the next Pod in line. Over the course of each day, this results in all the available Storage Pods being given the same opportunity to accept data at the same rate.
Backblaze claims the WD drives arrays were able to edge out the arrays filled with Seagate drives by a little over 1 TB per of I/O performance per day, on average. For example, the WD Pod loaded 5.12TB of data per day and Seagate's loaded 4.02TB per day.
For comparison purposes, Backblaze said it also deployed a Storage Pod filled with 4TB drives from HGST.
Last year, Backblaze began publishing hard drive study data, all of it culled from its massive data center containing nearly 40,000 hard drives. It has reported mostly on reliability. Most recently, though, it released data about which five of the 70 metrics that SMART stats cover are likely to predict a hard drive failure.
The report this past September claimed to show consumer hard drives were as reliable as enterprise-class models, if not more so.
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