{Spam?} Re: URGENT: Need help rebuilding iir RAID5 array with failed drive

[Derek Ragona]

At 04:10 PM 6/28/2008, Garrett Cooper wrote:
>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
>
>--

Garrett,

There is a setting in the matrix manager on some versions to set the 
rebuild rate.  It defaults to a low value like 30% so the array rebuild can 
take place with the OS still running and usable.  If the system is really 
doing nothing else, bump that value to 90-100%, it will rebuild MUCH faster 
then.

         -Derek

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