Recovering from a RAID failure.

Trent Nelson tnelson at
Wed May 21 08:03:59 PDT 2003

On Wed, May 21, 2003 at 10:44:13AM -0400, Bill Moran wrote:
> Trent Nelson wrote:
> >    Long story short; had a RAID array, disks failed in such a way that
> >    the config info was lost.  I know that one disk is still good, and
> >    as it was a mirrored set, I'm sure the data on it is still good.
> >    However, with ar0 dying, so did my disklabel/fdisk information.
> >
> >    If I can recreate (from memory) the appropriate disklabel/fdisk info
> >    for the disk that's still good (ad6), I should be able to access ev-
> >    erything as per normal (i.e. mount file systems again), shouldn't I?
> Yes.  As long as you get it exact.

    Getting it exact is going to be fun.
> Hope you have backups.

    *no comment*

> Out of curiosity: what kind of array?  Hardware?  What brand?

    Sil 680 ATA133 IDE controller that does RAID.  It was a mirrored
    RAID set using two 60GB Maxtor drives (6Y060L0).  ad4 was experi-
    encing failures, and ad6 was already a new 60GB drive following
    the failure of a previous drive and Maxtor's neat advanced RMA 
    option.  ad4's replacement arrived yesterday, an 80GB 8MB cache
    Maxtor, which I can't complain about.

    For some reason, the RAID config was only stored on ad4 as far
    as I could work out.  It needed to be up in order to boot, but
    I kept it detached via atacontrol (thus operating the array in
    degraded status) after booting.  Unfortunately, this morning,
    it failed all together in some weird way, so I could no longer
    boot off it, the Sil RAID manager reported an invalid RAID set,
    and the fdisk/disklabel info for ar0 was lost.

    There's nothing I fear more now than the dodgy clicking sounds
    all new HDDs seem to make after a month or so in this box. (It 
    is an Athlon XP 1800+, 1GB PC2700 DDR, Asus A7V8X m/b.)  It's
    always a given for imminent HDD failure.

    Happy times.  Oh happy times.


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