[CentOS] Software RAID1 with CentOS-6.2

[Kahlil Hodgson]

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

-- 
Kahlil (Kal) Hodgson                       GPG: C9A02289
Head of Technology                         (m) +61 (0) 4 2573 0382
DealMax Pty Ltd                            (w) +61 (0) 3 9008 5281

Suite 1005
401 Docklands Drive
Docklands VIC 3008 Australia

"All parts should go together without forcing.  You must remember that
the parts you are reassembling were disassembled by you.  Therefore,
if you can't get them together again, there must be a reason.  By all
means, do not use a hammer."  -- IBM maintenance manual, 1925