Re: [Bug-ddrescue] GNU ddrescue 1.18-pre3 new option complication

[Scott Dwyer]

It sounds like you have figured out the "tricky" part. I had thought 
about suggesting doing the "re-open" before skipping ahead due to slow 
speed, and if the speed didn't go up then skip ahead. But it sounds like 
you have a much better combination of ideas than I was coming up with. I 
do agree that once past the "fast" copy stage, there is not really a 
need to try to increase the speed, especially if going slower helps the 
read chances.

As for the skip rate, that still sounds a bit tricky.


On 8/27/2013 7:41 PM, Antonio Diaz Diaz wrote:
> The kernel code linked by Sam gave me some ideas. It seems the kernel 
> counts the number of different classes of errors occurred in the last 
> 5 or 10 minutes. So it may be a good idea to fly away from errors 
> _and_ slow areas.
>
> I have just uploaded version 1.18-pre4[1] with the effect of 
> '--reopen-on-error' limited to the copying phase, but reopening the 
> input file also on slow reads (i.e., every time ddrescue skips ahead).
>
> A slow speed while reading sector by sector (while trimming, splitting 
> and retrying) may help to read more sectors, as the kernel developers 
> intend.
>
> I have also changed the default value of '--min-read-rate' to 0 
> (auto), so that slow areas are skipped by default. Maybe the default 
> value (average_rate / 10) is too low and will need furter adjustment.
>
> [1]http://download-mirror.savannah.gnu.org/releases/ddrescue/ddrescue-1.18-pre4.tar.lz 
>
>
>
> Hope this helps,
> Antonio.
>
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