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Date:      Wed, 15 Oct 2008 06:15:46 -0700
From:      Jeremy Chadwick <koitsu@FreeBSD.org>
To:        Jon Theil Nielsen <jontheil@gmail.com>
Cc:        freebsd-questions@freebsd.org, freebsd-hardware@freebsd.org
Subject:   Re: RAID 5 - serious problem
Message-ID:  <20081015131546.GA78192@icarus.home.lan>
In-Reply-To: <8f82c35c0810150532o52ae50b5kef7c685fd23a0af4@mail.gmail.com>
References:  <8f82c35c0810150532o52ae50b5kef7c685fd23a0af4@mail.gmail.com>

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On Wed, Oct 15, 2008 at 02:32:25PM +0200, Jon Theil Nielsen wrote:
> Dear list,
> 
> Something happened that I don't think should be possible. I "lost" all three
> disks in my RAID 5 array simultaneously after approx. two years without any
> problem. And I fear I will never see my data again. But I really hope some
> of you clever persons can give me some hints. My system is:
> FreeBSD 7.0-Release
> Intel D975XBX2 motherboard (Intel Matrix Storage Technology)

Are you using the Matrix Storage Technology?  If so, immediately stop.
FreeBSD's support for this is very, very bad, and will nearly guarantee
data loss.  There are many of us who have tried it, and it's known to
be buggy on FreeBSD.

http://wiki.freebsd.org/JeremyChadwick/ATA_issues_and_troubleshooting

I recommend you stop using this feature and start using ZFS or gvinum
for what you need.

> 3 WD Raptor 74 GB in a RAID 5 array
> 1 WD Raptor 150 GB as a standalone disk
> / and /var mounted on the standalone,, /usr on the RAID 5
> I believe what happened was that one of the disks didn't respond for such a
> long time, that is was marked "bad". And afterwards the same thing happened
> for the other disks. When I try to boot the system, all three disks are
> marked "Offline".
> The BIOS utility for the host controller has no option to force the disks
> back online.
> I have another machine with a S5000XVN board and Intel Embedded Server RAID
> Technology II. The BIOS configuration utility on this board has the option
> to force offline drives back online.

Any "embedded" RAID is usually BIOS RAID managed by either a "software
RAID IC" (e.g. an IC on the motherboard that handles LBA/CHS addressing
for creating a pseudo-array, but the OS still does all of the management
and does not off-load anything).

> I am very desperate not to lose my data, so I don't know if I dare moving
> the drives to the other machine and try to make them online again. Do you
> think I should try?

No, but you might not have any choice.  It honestly sounds like the
metadata on your disks is in a bad state.

I would recommend you try booting Linux, since their support for
MatrixRAID is significantly better/more advanced.  Ideally, you should
be able to bring the RAID members back online using their tools, then
reboot into FreeBSD and cross your fingers that your data becomes
accessible.  Once accessible, offload it somewhere immediately, and
follow my above recommendations.

> In general, are there any procedures I can try to recover my RAID array? Or
> is the offline status definitive ? and all data definitely lost? I guess
> some specialized companies have the expertise to recover lost data from a
> broken RAID array, but I don't know. And I don't know the price of such a
> service.
> I would really, really appreciate any kind of help.
> I have backups of most user data, but not of the system configuration (and
> maybe even not the databases).  This is of course pretty stupid. In the
> future, I will not rely on RAID 5 as a foolproof solution?

RAID 5 is a fine solution, but you have learned a very valuable lesson,
one which I will enclose in asterisks to make it crystal clear: ***RAID
DOES NOT REPLACE BACKUPS***.  Repeat this mantra over and over until you
accept it.  :-)

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |




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