identical disk dump

Les Mikesell lesmikesell at gmail.com
Tue Feb 14 18:54:36 UTC 2006


On Tue, 2006-02-14 at 12:36, Mikkel L. Ellertson wrote:

> > I need to make an identical bit-for-bit transfer of a hard disk from a
> > *REALLY* slow box to a faster box.
> > 
> > 1- There are no security issues --plugging one box directly into the other.
> > 2- I need to prove/document the copy is identical to the original.
> > 3- I want to do it as efficiently as possible.
> > 4- I "own" both boxes.
> > ---
> > Has anyone used dcfldd ?? Is this a better tool than dd ??
> > http://dcfldd.sourceforge.net/
> > ---
> > Any time-tested commands/flags/scripts would be greatly appreciated.
> > 
> > Best wishes to everyone,
> > 
> > Andrew
> > 
> If you are going from one box to another, then dd type tools are
> not the right tool for the job. You may want to take a look at
> Ghost 4 Linux ( http://freshmeat.net/projects/g4l/ ) This also
> has the advantage that the drives are not mounted during the
> copy, so you do not have to worry about something changing while
> the drive is being copied. You do NOT want to do a bit-for-bit
> copy of a mounted drive!

You can use dd even across machines if you can boot a
run-from-CD distro that has ssh like knoppix.  Set a root
password and start the ssh server on the remote box
and use a command like:
dd if=/dev/hda |ssh remote_ip dd of=/dev/hda
However, to use dd the disks must be the same size. If this
completes without errors, the disks will be bit-for-bit
identical.  You will have to change a few bits, though. One
change will be to delete and re-add the ethernet interface(s)
or edit and remove the HWADDR= entries from
/etc/sysconfig/network-scripts/ifcfg-eth* file(s).  Otherwise
the interface(s) will be ignored because the MAC address won't
match the new box.  You may also have a problem if the
new box needs a disk driver that isn't compiled in the
kernel or included as a module in the initrd image. 

-- 
  Les Mikesell
   lesmikesell at gmail.com




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