Re: URGENT: Need help rebuilding iir RAID5 array with failed drive

On Sat, Jun 28, 2008 at 11:30 AM, Derek Ragona
<derek_at_computinginnovations.com> wrote:
> At 05:49 AM 6/28/2008, you wrote:
>
> On Sat, Jun 28, 2008 at 2:02 AM, Søren Schmidt <sos_at_freebsd.org> wrote:
>>
>> Erm, this makes no sense at all. You state you use the "iir" driver for
>> the
>> card, yet you expect to see the devices under ATA ?  Those are two very
>> different animals, you can't use them together in away way or fashion on
>> the
>> same drives.
>>
>> That asks the question: which one is it ?
>>
>> If you use "iir" I have no idea how/if a rebuild is possible under
>> FreeBSD,
>> however it could be in the BIOS or with any other OS that supports it
>> (here
>> the HW should have kept your parity data intact).
>>
>> If you use ATA you shouldn't have used RAID5 as the docs tell you, as
>> there
>> will be no parity data to rebuild from no matter what BIOS/OS you use ->
>> you
>> will get garbage no matter what.
>
> Uhm... ok, I'll bite. What documentation states how to use RAID's
> under FreeBSD properly? The GEOM docs didn't seem to be what I was
> looking for back then.
>
>>> Thanks for the help and support. This definitely served as a lesson to
>>> backup my data more often...
>>
>> That by itself may be worth all the trouble :)
>
> No doubt.
>
> Thanks :),
> -Garrett
>
> You can either use the built in RAID software in FreeBSD or use the hardware
> makers RAID outside FreeBSD.
>
> If you use the internal FreeBSD for a software RAID, most recommend you use
> the RAID for non-boot, using a separate disk to boot from.  Basically using
> a smaller drive for / so the system is bootable and configurable with or
> without RAID.  Then add your RAID after installing FreeBSD.
>
> If you choose to just setup a RAID array in the hardware, then usually
> FreeBSD just see this volume as one large single drive you can partition and
> use like one huge virtual disk.  In the case of errors or failures you need
> to check the console logs when the system boots.  I wouldn't recommend this
> method UNLESS you do RAID 10 with hot spare drives.  So any drive failures
> are rebuilt for you, so errors on reboots will still need to be checked, but
> just to see if a drive needs to be replaced.
>
> Depending on the systems use, you may find it easier to use one of the
> "packaged" solutions  based on FreeBSD, such as:
> www.freenas.org
> or
> http://m0n0.ch/wall/

Thanks for the comments Derek, Soren, and Ed.

FWIW (I've discovered this through personal experience and reading a
lot of docs), the only way to get "hardware RAID" with iir and the
ICH9R chipset is through the Matrix Manager (either by creating one at
the BIOS level console or Windows -- bleh). FreeBSD spotted it as a
single drive (/dev/ar0), so at that point it was being managed by the
southbridge.

Performance sucks, the array rebuild takes eons (16 hours for adding a
1TB drive to an existing 4 x 750GB drive array with an Core 2 E6700
with 2GB RAM under Vista x64) and the rebuild console is _only_
available under Windows =(.

At least it's keeping the filesystem intact though, long enough for me
to make a redundant copy of the data then move all this junk over to
another safe place while I grab DVD+R/W's and wait for my 3ware card
to come in the mail..

Thanks,
-Garrett