Constant messages on I/O error on same sectors

Solution 1:

Your drive is failing, and this is likely irreparable.

=== 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       90%     23618         1476686720
# 2  Extended offline    Completed: read failure       90%     23618         1476686720

This means that when you ran a self test with smartctl -t long, the result was a read failure about 10% of the way into the drive. It doesn't tell you the result as part of the smartctl -t command, because this would tie up your terminal for several hours - it should tell you how to access the results.

Continuing to use the drive may result in silent data corruption, or complete failure. I'd strongly suggest replacing it.