[CentOS] smartd and smartctl

Fri Feb 17 20:25:09 UTC 2012
m.roth at 5-cent.us <m.roth at 5-cent.us>

Mike Burger wrote:
>
>> A few weeks ago, one of my servers started complaining, via smartd, that
>> one drive had one unreadable sector. I umounted it, and ran an fsck -c,
>> then remounted it. Error didn't go away. Now, what's really annoying is
>> that I've gotten back to it today, and it's reporting the problem, as it
>> has for weeks now, every half an hour.
>>
>> However, when I run
>>> smartctl -q errorsonly -H -l selftest -l error /dev/sdb
>> it gives me *nothing*. Anyone understand why I get two different
>> results?
>>
>>      mark "and I am waiting for the smartctl -t long /dev/sdb to
>> complete"
>
> The smart system works at the hardware level, reading diagnostic
> information from the SMART circuitry on the hard drives, themselves. The
> hard drives will often, now, try to move the data from bad sectors on the
> platters to good sectors, and then mark them so that they won't be used,
> later.
>
> Running fsck only works at the logical filesystem layer. The fsck tool has
> no hooks to deal with the physical layer.

Ok, but my thinking was, first, that after the fsck, the system wouldn't
try to write to the bad sector, thus not provoking smart. The more
annoying thing is that I don't understand why smartctl doesn't give the
same info as smartd. When I do a -a, it does tell me that one sector's
pending, but not that there's any error.

        mark