We are constantly looking at new hard drives, evaluating them for reliability and power consumption. The Hitachi 3TB drive (Hitachi Deskstar 5K3000 HDS5C3030ALA630) is our current favorite for both its low power demand and astounding reliability. The Western Digital and Seagate equivalents we tested saw much higher rates of popping out of RAID arrays and drive failure. Even the Western Digital Enterprise Hard Drives had the same high failure rates. The Hitachi drives, on the other hand, perform wonderfully.
We see fairly high infant mortality on the hard drives deployed in brand new pods, so we like to burn the pods in for a few days before storing any customer data. We have yet to see any drives die because of old age, which will be fascinating to monitor in the next few years. All told, Sean replaces approximately 10 drives per week, indicating a 5 percent per year drive failure rate across the entire fleet, which includes infant mortality and also the higher failure rates of previous drives. (We are currently seeing failures in less than 1 percent of the Hitachi Deskstar 5K3000 HDS5C3030ALA630 drives that we’re installing in pod 2.0.)