Is SMART Really Smart?
The short answer is no. SMART was designed to catch disk errors early enough so that you can back up your data. But according to Google, more than one-third of all failed drives did not trigger an alert in SMART. This isn't a huge surprise, as many industry insiders have been suspecting this for years. It turns out that SMART is really optimized to catch mechanical failures. Much of a disk is still electronic, though. That's why behavioral and situational problems like power failure go, unnoticed while data integrity issues are caught. If you're relying on SMART to tell you of an impending failure, you need to plan for additional layer of redundancy if you want to ensure the safety of your data.