Three Googlers, Eduardo Pinheiro, Wolf-Dietrich Weber and Luiz Andr´e Barroso, have released a study on disk drives and their failure rates in a large population.

The study surveyed 100,000 drives of different specifications from various manufacturers. They founds that often times drives using only SMART specifications (designed to monitor drive health) did not accurately predict the drive failures.

Even more interesting is that they found drive temperature and activity were less of a factor than previously thought.

The moral of the story - all drives will fail and often times without warning.

Failure Trends in a Large Disk Drive Population - (PDF Link)