Restoring Data from a DD image
Gayn Winters
gayn.winters at bristolsystems.com
Thu Oct 6 14:24:10 PDT 2005
> -----Original Message-----
> From: Bill Schmitt (SW) [mailto:software at schmittnet.com]
> Sent: Thursday, October 06, 2005 1:16 PM
> To: gayn.winters at bristolsystems.com
> Cc: questions at freebsd.org
> Subject: Re: Restoring Data from a DD image
>
>
> Gayn Winters wrote:
>
> >>-----Original Message-----
> >>From: owner-freebsd-questions at freebsd.org
> >>[mailto:owner-freebsd-questions at freebsd.org] On Behalf Of
> >>Bill Schmitt (SW)
> >>Sent: Thursday, October 06, 2005 11:11 AM
> >>To: questions at freebsd.org
> >>Subject: Restoring Data from a DD image
> >>
> >>
> >>I've just replaced a hard disk that was dying fast. I've
> done a full
> >>installation of 4.9 (later releases won't install, which I've
> >>submitted
> >>a problem report on already). The old disk is connected but
> >>not mounted.
> >>Searching around, I found some suggestions to try to read the
> >>old disk
> >>to restore what I can and I used dd to copy what could be found (dd
> >>-if=/dev/ad0s1e of=/usr/olddsk/oldimag.dmg
> conv=noerror,sync) and it
> >>seems to have copied the file. Now, I'm a little stuck. Can
> >>someone help
> >>me understand how do I mount that image somewhere to browse
> >>it and copy
> >>what I can from it? If I'm not going about this the right way, I'd
> >>appreciate other suggestions
> >>
> >>
> >>
> >
> >I'm a little confused:
> >
> >Did you try to copy (dd) the old disk before you did a new install?
> >If so, to where?
> >
> >Is /dev/ad0 your new disk with the fresh 4.9 installation on
> ad0s1? Or
> >did you just add a new disk as /dev/ad1 and did the fresh install on
> >ad1s1?
> >
> >Is your unmounted old disk /dev/ad0 or /dev/ad1 now?
> >
> >I'm guessing that ad1 is your new install, ad0 is not
> mounted, and you
> >were able to copy ad0s1e to oldimag.dmg with the above dd
> command. If
> >so, continue. If not, send a correction.
> >
> >Why not try
> > mount -r -t ufs /usr/olddsk/oldimag.dmg /mnt
> > cd /mnt
> > ls
> >
> >I ***think*** mount will do this. If not, try dd'ing
> oldimag.dmg to a
> >spare slice, e.g. if you created /tmp as /dev/ad1s1e, then you could
> > dd if=/usr/olddsk/oldimag.dmg of=/dev/ad1s1e
> > cd /tmp
> > ls
> >
> >Good luck!
> >
> >-gayn
> >
> Sorry, when I first decided to try FreeBSD, I had a 4.7GB as
> the primary
> on ad0 and moved usr to ad1 when I added the drive that
> ultimately went
> bad (a 60GB) as ad1. When I had to do a full installation
> again, I put a
> new drive (80GB) into place where the 4.7GB drive was and
> started from
> scratch with ad1 disabled. So, now I'm booting from the new drive and
> have used dd to copy whatever is found on the damaged ad1 to
> an image on
> ad0. It's after that I get stuck. I've looked at the man page
> for mount,
> but I haven't seen anything specific to an image. I tried your
> suggested mount command, but it responded "Block device required". I
> suppose I can try to dd back to the 4.7GB drive that I would
> now mount
> as ad1. We'll see what happens.
>
> Thanks,
>
> Bill
>
As Joe S suggests, use mdconfig or vnconfig to create the block device,
then mount works. (I tried it with mdconfig using 5.4.) Dd'ing to a
spare slice or partition will surely work as well.
-gayn
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