Re: [Bug-ddrescue] Feature Suggestion: Automatic Cooldown mode

[David Deutsch]

> It is nice that speed is improving now, but the gain I was thinking about was 
> a sustained speed for a longer time before trimming.

Yeah well, clearly we can't always get what we want... ;-)

> In case you feel like trying reverse mode, take into account that reversing 
> direction in the middle of a rescue is tricky. (It continues backward from 
> the current position, not from the end).

Not sure I want to exchange "tricky" for this "great" run right now -
I mean, 6 days to reclaim 30GB from the first 500GB isn't great... but
it isn't terrible either. Particularly considering what the image for
the rest of the disc seems to look like - I think I will probably get
through it in two weeks. Or do you think this would significantly
increase the speed?

And: would your proposal make sense after I'm done with the current run?

cheers,
David

On Tue, Feb 4, 2014 at 9:15 PM, Antonio Diaz Diaz <address@hidden> wrote:
> David Deutsch wrote:
>>
>> Quick update - Seems like speed is indeed improving (slightly redacted
>> for space):
>
>
> It is nice that speed is improving now, but the gain I was thinking about
> was a sustained speed for a longer time before trimming.
>
>
>
>> Close to breaking 1750GB, too. I think this kills the "1/8 of the disc
>> is dead" idea, ie. one platter/side or read head being dead. Still
>> curious what could produce such a regular error, though. Particularly
>> across the entire space of the disc. Or maybe I just have no frigging
>> clue how hard discs werk (I really don't).
>
>
> To make things difficult, most probably every disc works differently. :-)
>
>
>
>> Reading still progresses in a steady pace in general, although it's
>> kind of weird: It only reads every two to three minutes, sometimes up
>> to ten. Not sure whether that is the drive hardware failing more, in
>> general (though speeds improving would say otherwise) or just the
>> general issue with bad sectors. Then again: Shouldn't it just skip
>> past those? Or are the sectors around the bad ones just hard to get
>> anything out of?
>
>
> The sectors around the bad ones are hard to get out of.
>
>
>
>> This is what it looks like now in ddrescueview, btw:
>
>
> I am just now testing an idea inspired by your images; making each copying
> pass run in the inverse direction as the previous one. This should read
> faster all those large non-tried areas remaining behind the large errors.
>
> In case you feel like trying reverse mode, take into account that reversing
> direction in the middle of a rescue is tricky. (It continues backward from
> the current position, not from the end). The following sequence makes the
> trick:
>
>   ddrescue your_options_and_files -i position -s 512
>   ddrescue your_options_and_files -R
>
>
> Best regards,
> Antonio.