[CentOS] Software RAID1 with CentOS-6.2

Hi Keith,

On Tue, 2012-02-28 at 16:43 -0800, Keith Keller wrote:
> One thing you can try is to download WD's drive tester and throw it at
> your drives.  It seems unlikely to find anything, but you never know.
> The tester is available on the UBCD bootable CD image (which has lots of
> other handy tools).

Ah cool. I'll give that a go :-)

> Which model drives do you have?  I've found a lot of variability between
> WDxxEARS vs their RE drives.

These are WD1002FAEX drives (qTB, SATA3, 7200rpm, 64MB).

> Supposedly, at least with RAID[456], the array is completely usable when
> it's resyncing after an initial creation.  In practice, I found that
> writing significant amounts of data to that array killed resync
> performance, so I just let the resync finish before doing any heavy
> lifting on the array.

Yeah.  That was my understanding. Thanks for the confirmation:-)

> > Anyway, I leave the system to sync for the rest of the day.  When I get back to
> > it I see the same (similar) I/O errors on the console and mdadm shows the RAID
> > array is degraded, /dev/sdb2 has been marked as faulty.  This time I notice
> > that the I/O errors all refer to /dev/sda.  Have to reboot because the fs is
> > now readonly.  When the system comes back up, its trying to resync the drive
> > again. Eh?
> 
> This sounds a little odd.  You're having IO errors on sda, but sdb2 has
> been kicked out of the RAID?  Do you have any other errors in
> /var/log/messages that relate to sdb, and/or the errors right around
> when the md devices failed?

Having a little trouble getting at the log files.  When it fails the fs
goes read-only and I can't run any programs (less, tail, ...) except
'cat' against the log file or dmesg output (I get I/O errors).  On
reboot there's nothing in the log files, presumably because they could
not be written to.  May have to have to set up a remote logging to get
at this (PITA). 
 
Thanks for the suggestions :-)

Kal

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