A pretty interesting read that I found over at Slashdot.
http://labs.google.com/papers/disk_failures.pdf
http://labs.google.com/papers/disk_failures.pdf
Google Inc. said:Overall, we expected to notice a very strong and con-sistent correlation between high utilization and higher failure rates. However our results appear to paint a more complex picture. First, only very young and very old age groups appear to show the expected behavior. Af-ter the first year, the AFR of high utilization drives is at most moderately higher than that of low utilization drives. The three-year group in fact appears to have the opposite of the expected behavior, with low utilization drives having slightly higher failure rates than high uti-lization ones.
One possible explanation for this behavior is the sur-vival of the fittest theory. It is possible that the fail-ure modes that are associated with higher utilization are more prominent early in the drive’s lifetime. If that is the case, the drives that survive the infant mortality phase are the least susceptible to that failure mode, and result in a population that is more robust with respect to varia-tions in utilization levels.
Another possible explanation is that previous obser-vations of high correlation between utilization and fail-ures has been based on extrapolations from manufactur-ers’ accelerated life experiments. Those experiments are likely to better model early life failure characteristics, and as such they agree with the trend we observe for the young age groups. It is possible, however, that longer term population studies could uncover a less pronounced effect later in a drive’s lifetime.