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

[David Deutsch]

Hi Scott,

Wow, no, I did not see that at all! Sorry for seemingly ignoring you
for days, now. Not sure whether it's my gmail account or something...
Weird. Probably because I messed up my replies in the beginning.

(replying to the points raised in that email since they also answer
your current questions)

> Both finished logs showed something interesting, in that there were many 
> small errors in what could almost be considered a spiral pattern

Yeah, that's pretty much exactly the thing with my drive - it seems
like all bad sectors found are 512 Bytes.

> The fun part was that the filesystem (it was an NTFS disk) was so messed up 
> that nothing would mount it

Maybe I got lucky there since I was using ext3.

> even testdisk failed to find a large portion of the files. So be prepared to 
> use something more robust than testdisk (like R-Studio) if you go through 
> with the rest of the recovery.

Yeah, that really is the scary part - Since we're talking about 1TB of
DSLR files (.JPG, .MOV) and music (flac, mp3) each, I would really
like to see this mounted. I have 'rescued' a number of disks for other
people and losing all the nice meta-data (directories etc.) would
be... quite a bummer. The music stuff I would probably just have to
redo from my CD collection... *sigh*

> ddrutility

>From what I understand that is mostly about your case, rescuing ntfs
partitions? Or would it help in my case as well?

> Third, I am interested in a copy of your logfile if possible. Actually I 
> would like the first one you sent to Antonio if you still have it, and also 
> your current one.

Sure thing. Will send them along in a separate message.

cheers,
David

On Wed, Feb 5, 2014 at 1:25 AM, Scott Dwyer <address@hidden> wrote:
> Hi David,
>
> First, did you see my reply with my 2 cents? It contained some info (my
> opinion) as to what might have happened to your drive, and what you might
> expect (from my experience). I only replied to the bug list, so if you did
> not see it then you will have to look into the archives which can be found
> through the ddrescue page.
> http://lists.gnu.org/archive/html/bug-ddrescue/
>
> Second, while errors are skipped, every error takes time to process, first
> by the drive itself and then that is multiplied by any op system retries
> (from what I can tell in linux from observation, it is about 15 retries
> normally, or 5 retries using the direct option). So if the drive takes 3
> seconds per error, then it would take 15 seconds with the direct option to
> process the error, or 45 seconds without the direct option. I used 3 seconds
> for the drive as that is about an average from a few drives I have seen, but
> that is dependent on the drive itself. Doing a little math on that means
> that at 15 seconds per error, you could process about 5760 errors per day.
> And you are going to have a LOT of errors by the looks of it, so you are in
> for a long recovery. But don't be too discouraged just yet. You will have
> many errors spread all over, but there is still a chance that you will end
> up with 99% of good sectors vs bad, not to say that file recovery will be
> easy when done. What file system is this? Is is NTFS? What type of files
> will you be trying to recover?
>
> Third, I am interested in a copy of your logfile if possible. Actually I
> would like the first one you sent to Antonio if you still have it, and also
> your current one.
>
> Scott
>
>
>
> On 2/3/2014 5:00 PM, David Deutsch wrote:
>>
>> 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).
>>
>> 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?
>
>