I have a disk in a two-disk software RAID-1 for which recently an "offline uncorrectable sector" appeared in the SMART status.
198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 1
This apparently is only a sign of imminent disk failure if it occurs increasingly frequently (and since the drive is mirrored, there is no great risk of real data loss either). At the time, a self test also failed at some point and
smartd sent me an email to notify me of this as it of course should do.
However, writing to the damaged sector usually causes the disk to use one of its spare sectors instead which it apparently did because since I
dded over the disk, all self-tests ran through just fine. And
badblocks also found no reason to complain.
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error [...] # 5 Extended offline Completed without error 00% 5559 - # 6 Short offline Completed without error 00% 5540 - # 7 Short offline Completed: read failure 90% 5524 63273368
The number of faulty sectors didn't decrease though which it shouldn't, really, since the broken sector's still there, albeit unused. However,
smartd continues to send me emails every night:
The following warning/error was logged by the smartd daemon: Device: /dev/sda [SAT], 1 Offline uncorrectable sectors
This is extremely annoying obviously and numbs my healthy panic reflex to
The disk is a Western Digital WD20EARS and the
smartd version is 5.41 2011-06-09 r3365.