[olug] using dd to clone a drive

Kevin sharpestmarble at gmail.com
Mon Apr 18 19:12:13 CDT 2016

The copy won't complete(I tried it with a similar situation). What I wound
up doing is manually creating a filesystem on the new drive, mounting both
filesystems, and then using rsync to copy the files over.

I think I used CentOS.

You can check the status of dd by sending it a -USR1 signal. Note that
you'll have to send the dd process itself the signal, not sudo or su or any
other similar process. From dd(1):

       Sending a USR1 signal to a running 'dd' process makes it print I/O
statistics to standard error and then resume copying.

              $ dd if=/dev/zero of=/dev/null& pid=$!
              $ kill -USR1 $pid; sleep 1; kill $pid

              18335302+0 records in 18335302+0 records out 9387674624 bytes
(9.4 GB) copied, 34.6279 seconds, 271 MB/s

On Sun, Apr 17, 2016 at 10:53 PM, Jay Bendon <jaybocc2 at gmail.com> wrote:

> The copy will complete.  Those read errors will turn into block errors on
> the destination disk.  It will complete but data may not be available
> depending on the number of errors.
> --Jay
> On Sun, Apr 17, 2016 at 8:43 PM, Tom Williamson <twilliam at inebraska.com>
> wrote:
> > I tried to use dd to clone a 1 GB drive to another 1 GB drive. I had been
> > getting warnings of "many bad sectors" on the one I was trying to copy
> > from. When I ran the command, there was no error message, but I could not
> > tell if anything was happening. How long should this process take? Will
> the
> > bad sectors prevent the copying from being able to complete the process?
> I
> > did see some conditional commands about errors, but I was not sure if
> this
> > would do what is needed to clone the image.
> >
> > I am using a live disk with ubuntu 14.04, to execute the process in a
> > terminal. This is a 32bit machine that I am working on and the first try
> > did not show that anything was done after 10 to 12 hours. I started in
> the
> > early evening an let it run over night.
> >
> > Any ideas and information would be appreciated.
> >
> > Thanks
> >
> > Tom Williamson
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