Comment 10 for bug 412152

"Pre-fail" is the type of attribute in SMART, not the status of your particular drive. When a pre-fail attribute rises unusually or reaches a threshold, it's a sign that the drive will die in a very short time period (as small as 24 hours).

Contrast this to "old-age" attributes which can reach the threshold, but the drive may continue to function for an indeterminate time.