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Date:      Sun, 5 Aug 2012 23:28:45 -0700
From:      Michael Sierchio <>
To:        Matthew Navarre <>
Subject:   Re: Mounting raw disk backup file.
Message-ID:  <>
In-Reply-To: <>
References:  <>

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On Sun, Aug 5, 2012 at 11:12 PM, Matthew Navarre

> I had a drive fail recently, it was working fine until I rebooted. After
> that the partition map was corrupt and I can't mount either partition on
> the disk. So I made a copy of the whole disk using dd to an old USB drive.
> There were several IO errors while dd was copying the disk, so I think the
> disk is starting to go.
> I can probably fix the partition table using testdisk, but now that I've
> got this image file I'd rather work with that instead of the physical disk.
> I've read the Handbook section on using mdconfig, but that assumes the
> image file is of a filesystem, not a whole disk. I think I've
> found instructions for how to do it on linux, but if there's a way to mount
> it on FreeBSD I'd rather do that.
> So, any suggestions?
> Here's what file says about the file:
> mnavarre@pcbsd-1810] /# file /mnt/ada1_backup
> /mnt/ada1_backup: x86 boot sector; partition 1: ID=0xa5, active, starthead
> 1, startsector 63, 167766732 sectors; partition 2: ID=0xa5, starthead 254,
> startsector 167766795, 144809910 sectors, code offset 0x3c, BSD disklabel
Why did you put it in /mnt?  That's customarily used for mounting
fileystems.  Move it ;-)

mdconfig -a -t vnode -f /new-path/ada1_backup

note the device that's created (probably md0)

you can then operate on /dev/md0 as if it were a disk.  In particular, you
might want to fix the partition map, the label info, etc.  You can then
fsck the filesystem (presumably something like /dev/md0s1a or /dev/md0a

You'll probably need to tell fsck that it's ufs (i.e. fsck -t ufs /dev/md0a

you can then mount the fs (mount -t ufs /dev/md0a /mnt )

- M

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