Re: [Bug-ddrescue] Dealing with a disk that stops responding

[Antonio Diaz Diaz]

Hello Olaf,

Olaf Buddenhagen wrote:
> But even if the verify worked in principle, it seems of limited use in
> its current form. For one, AIUI it only works when there was already a
> successfull read in the same run of ddrescue; while a failure on the
> first attempted block will still cause ddrescue to mark the rest of the
> disk as failed?

True. Versión 1.21-rc1[1] hopefully fixes this problem:

[1] http://lists.gnu.org/archive/html/bug-ddrescue/2016-01/msg00014.html
 * Option '-J, --verify-on-error' now exits with status 1 if a read 
error happens before a good sector is found.


> Also, it seems to me that verify failure is handled like a write error
> on the output file -- which means it will never put information about
> the failing cluster in the log file?

True. But I'm changing it because it seems more useful to mark the 
cluster as failed.


> For now, I'm working with -X, which is somewhat helpful. It's a rather
> manual process though, as it puts the actual failed cluster in the log
> file, but nothing after that -- so the next attempt (after a power
> cycle) would always continue with the next cluster: there is no way to
> automatically skip a bigger chunk.

The only way of automatically skipping a bigger chunk is to mark the 
following (or preceding) cluster(s) as failed, which I am not sure is 
generally a good idea.


> Also, -X only works for the first pass (copy) -- it looks like
> proceeding with trimming/scraping after that will be an even more manual
> process...

During trimming/scraping/retrying errors are expected, so -X didn't seem 
too useful there. But I can extend -X to all phases if it helps.


> Any suggestions how to address these problems?

I'll release a test version with modified -J and -X ASAP (maybe today). 
As always, feedback is welcome.


Best regards,
Antonio.