I bought this (1TB Seagate Barracuda 7200.12 - ST31000528AS) drive about 18 months ago because it had a 5-year warranty, and used it alongside a Samsung Spinpoint under Ubuntu Server as one half of a software RAID-1 array.

Yesterday, smartd started reporting a problem:

Jan 18 06:08:03 svr smartd[2672]: Device: /dev/sdb [SAT], 2 Currently unreadable (pending) sectors
Jan 18 06:08:03 svr smartd[2672]: Device: /dev/sdb [SAT], 2 Offline uncorrectable sectors
This repeats several times - though it has not been seen in the logs in the past few hours.

I followed this up by investigations with smartctl... and, after scheduling some tests, I get these results:

$ smartctl -l error /dev/sdb
smartctl 5.41 2011-06-09 r3365 [x86_64-linux-3.0.0-14-generic] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF READ SMART DATA SECTION ===
SMART Error Log Version: 1
No Errors Logged

$ smartctl -l selftest /dev/sdb
smartctl 5.41 2011-06-09 r3365 [x86_64-linux-3.0.0-14-generic] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF READ SMART DATA SECTION ===
SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Extended offline    Completed: read failure       10%     12451         1953523918
# 2  Short offline       Completed: read failure       90%     12445         1953523918
# 3  Short offline       Completed: read failure       60%     12445         1953523918
# 4  Extended offline    Completed without error       00%      5532         -

$

Only the 'selftest' output documents any kind of a problem - though I'm not 100% clear how to interpret it.  I suspect I may have scheduled two short tests at the same time... though I'm not sure why one has 90% remaining and the other 60%.  Come to that, I can't see why my long test has 10% remaining.

Another curious thing is that Raid-1 hasn't detected any kind of problem (or, at least, that's what I understand "[2/2][UU]" means.  While there are three partitions on sdb, only one is not trivially small... Of the other two, one is a boot partition (replicated between both drives for disaster recovery) and the other is swap.

$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdb3[1] sda3[0]
      967843840 blocks [2/2] [UU]

unused devices: <none>
$

A few questions...
Any advice/comments warmly appreciated... :)