[CentOS] Disk error

[Brian Mathis]

On Mon, Jan 7, 2013 at 5:58 PM, Emmett Culley <emmett at webengineer.com> wrote:
> For some time I have been seeing disk errors in the syslog every seven days.  Until today it always happens Sunday morning at 8:13 AM, plus or minus a minute or two.  Yesterday it happened at 1:13 AM.  Here are the pertinent log entries for the latest occurrence:
[...]
> Jan  6 01:13:25 g2 kernel:         res 51/40:00:db:bf:d6/40:00:04:00:00/00 Emask 0x9 (media error)
[...]
> Jan  6 01:13:25 g2 kernel: sd 8:0:0:0: [sdg] Add. Sense: Unrecovered read error - auto reallocate failed
[...]
>
> There is nothing in /etc/cron.weekly, nor are there any root crontab entries.  Any suggestions for investigating this issue would be much appreciated.
>
> Emmett
>


Based on this I'd say your disk is going bad, and has run out of spare sectors:
    Jan  6 01:13:25 g2 kernel: sd 8:0:0:0: [sdg] Add. Sense:
    Unrecovered read error - auto reallocate failed

You can use smartctl to get some information from the SMART tables,
but I've never been able to get a conclusive test out of the testing
options.  It would be a good idea to run 'badblocks' against the drive
as well, as it will definitely tell you if there are bad sectors.

Disks are so cheap it's usually not worth too much effort or delay
once you've found out that it's bad.


❧ Brian Mathis