Hard Disk Monitoring

I have a make-shift server with:

• LSI 9260-8i RAID card
• RAID 100
• 4 - 2TB 3.5 HDD

I was alerted that one of the drives failed. I replaced the drive and the array was automatically rebuilt without issue.

I tested the failed drive by placing it in a USB 3.0 caddy and ran HD Sentinel. I performed the following tests:

• Short Self-test
• Long Self-test
• Reinitialize disk surface (default settings)

Log file: All tests passed so is the drive safe to use (add back to array)? What made it fail, originally?

If the disk tests passed, so all recommended tests at

https://www.hdsentinel.com/faq.php#tests

1) Disk -> Short self test
2) Disk -> Extended self test
3) Disk -> Surface test -> Read test
4) Disk -> Surface test -> Reinitialize disk surface

do not show errors, then yes, the hard disk is safe to use. Then all problems (the one bad sector in this case) already found and corrected: now the spare area is used instead of the original bad sector.

Generally very small amount of bad sectors can be acceptable and usually then the hard disk can be used without problems, as described at

https://www.hdsentinel.com/faq.php#health

but as you can see, even one such reallocation may cause that the hard disk was not responding during the reallocation procedure and then the RAID controller disconnects the hard disk because of a timeout. So this could degrade the array, as you can see.

Ideally all disks should be tested by the above methods before making a RAID array on them, exactly to reveal / stabilize such issues before that could cause a degraded RAID array.

You may re-use in the array but only with constant monitoring to reveal/show possible further issues.