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

[Robert Backhaus]

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
>