"Vincent Danen has some tips for using the smartmontools package to obtain important information about the health of your hard drives that could provide early warning signs of problems.
"Computer hard drives today come with SMART (Self-Monitoring, Analysis, and Reporting Technology) built-in, which allows you to see the status or overall “health” of a hard drive. This information is invaluable in providing early warning signs of problems with a hard drive.
"All Linux distributions provide the smartmontools package, which contain the smartctl program used to display SMART information from attached drives. This package also provides the smartd daemon which periodically polls the drives to obtain SMART information."