White Papers
It is estimated that over 90% of all new information produced in the world is being stored on magnetic media,
most of it on hard disk drives. Despite their importance, there is relatively little published work on the failure
patterns of disk drives, and the key factors that affect their lifetime. Most available data are either based on
extrapolation from accelerated aging experiments or from relatively modest sized field studies. Moreover,
larger population studies rarely have the infrastructure in place to collect health signals from components in
operation, which is critical information for detailed failure analysis.
We present data collected from detailed observations of a large disk drive population in a production Internet
services deployment. The population observed is many times larger than that of previous studies. In addition
to presenting failure statistics, we analyze the correlation between failures and several parameters generally
believed to impact longevity.
Our analysis identifies several parameters from the drive’s self-monitoring facility (SMART) that correlate
highly with failures. Despite this high correlation, we conclude that models based on SMART parameters
alone are unlikely to be useful for predicting individual drive failures. Surprisingly, we found that temperature
and activity levels were much less correlated with drive failures than previously reported.
