Re: How to use a second source disk for a second pass with ddrescue

[Robert Trevellyan]

Alternatively, specify 1 or more retry passes.

Robert Trevellyan


On Mon, Oct 28, 2019 at 5:52 PM Robert Backhaus <address@hidden> wrote:

> You need to specify -A (--try-again), or it won't retry reading blocks that
> were previously marked as bad. This will work as long as both disks really
> are identical - especially watch out that there is no offset.
>
> On Tue, 29 Oct 2019 at 07:47, King Marzo <address@hidden> wrote:
>
> > Hi,
> >
> > I'm trying to use ddrescue to recover the data from a Linux raid 1 where
> > both disks have errors. I ran ddrescue to get the data from the first
> disk
> > onto a new disk, but I'm not sure how to run it on the second disk, and
> > I've scoured the Internet for two days now and can't find what command I
> > actually need to run to do this. I thought all I needed to do was to run
> > the exact same command as I did for the first disk but just change the
> > source drive to the second disk.
> >
> > I first ran: sudo ddrescue -f -n /dev/sdb1 /dev/sdd /root/recovery.log
> > Once that had completed, I ran: sudo ddrescue -f -n /dev/sdc1 /dev/sdd
> > /root/recovery.log
> >
> > Note that all I did was change the source drive from sdb1 to sdc1, but
> the
> > second pass instantly completes with the exact same summary as the first
> > pass, so I get the impression that it didn't do anything at all...but
> maybe
> > I'm not doing it right?
> >
> > Sorry if this is not the right place to ask questions about this, but I
> > couldn't find any forum for this or IRC channel or anything, and the gnu
> > page for ddrescue did say to write to this email address for help, so I
> > hope it was alright to email this address. Or if not, do you know of a
> > better place that I could ask this question? Thanks!
> >
> > Sincerely,
> >
> > David
> >
>