hardware mirrors recognized as individual disks in fbsd

Jerry McAllister jerrymc at msu.edu
Tue Jan 23 15:23:49 UTC 2007

On Mon, Jan 22, 2007 at 07:16:59PM -0600, Damian Wiest wrote:

> On Tue, Jan 16, 2007 at 11:33:47AM -0700, Steve Franks wrote:
> > I'm tired of win2k crashing, and we won't even go into my opinion of vista's
> > strongarm marketing tactics (read: changing my hardware means I have to pay
> > again? they can keep their OS).
> > 
> > Problem is, I've got 320GB of accumulated detrius on ntfs volumes to
> > migrate.  I see there is some good r/w ports for ntfs, so I'm willing to
> > evaluate that to see if it's stable (shoestring budget here obviously - this
> > is my personal stuff only).
> > 
> > Forging ahead, I get ready to start playing the mounting game, but
> > lo-and-behold, suddenly I have 4 disks whereas in windows I had two.  Now I
> > praise FreeBSD for it's superior intellect here, but now I have a problem.
> > I want two 160GB mirrored volumes, not 4 unmirrored ones.  The RAID is an
> > ASUS P5DR1-VM motherboard with a ULI raid chipset onboard.  Very nice setup
> > for the money.
> > 
> > Is this normal?  Am I going to break my mirror if I mount a single disk?  If
> > so, how do I mount a mirror?

First, I am guessing that what you say is just correct - somehow you
are seeing your disks in a non-raid form rather than treating it as
a raid.

Second of all, if you mount one side of the mirror as read-only, and
use that to read up what is on the drive, it should not break anything.
You can't write NTFS in FreeBSD anyway - or couldn't the last I knew.
You can only read NTFS in FreeBSD.

You should only have to read one disk of each of the two mirrors.
Then you can copy that stuff to some safe place - on another drive
probably - check it out and make sure it is ok and then reuse those
other 4 drives for something.   Maybe you can find a raid controller
that works or figure out how to use the one you have and use those
disks over again - now nicely reset to FreeBSD type (165) and with
FreeBSD filesystems built on them.

I have only used one raid in FreeBSD so far (and don't have it now) and 
it worked just fine after I figured out what driver it needed.  So, have
hope.   You can get it to work.

One more thing, is it at all possible that you are really seeing
four slices and two of them are vendor diagnostic/maintenance slices -
one for each raid rather than four actual disks?   Those don't show 
up in MS but FreeBSD sees them.   That occasionally throws people
when they think they should be on slice 1 (or slice 2 if dual booting)
and it is really slice 2 (or 3 for dual boot) because of the vendor
slice on the front of the drive.    Just an extra thought.


> > Thanks,
> > Steve
> > 
> > -- 
> > Steve Franks, KE7BTE
> > Staff Engineer
> > La Palma Devices, LLC
> > http://www.lapalmadevices.com
> > (520) 312-0089

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