Re: [Bug-ddrescue] ddrescue finalizing clone with 336KiB errsize

[Felix Ehlermann]

Dear Jake,

first of all:
This does not look like a ddrescue topic to me, so this might be the 
wrong mailing list for your question.

ddrescue will help you to read all "still readable" data from a broken 
disk - but after having done that, you'll need a different tool, 
depending on your filesystem, etc.


On 28.09.2011 20:27, Jake wrote:
> using ddrescue v1.14 on a SystemRescueCD USB drive to
> clone a 320GB IDE drive to a 640GB SATA drive
[...]
> right now and it has 615 errors.
[...]
> I want to reuse this drive to put back into the Windows XP
> system that I'm recovering from, but with 615 errors left will it work?

I don't know which drive "this drive" is that you want to put back in 
the XP box.
Is it the 320G or the 640G drive?

I hope you don't plan to re-use the 320G drive - I would never consider 
a HD which already has bad blocks to be reliable and I would never use 
it for storing data on it.
(And looking at current price levels for new disks a replacement will be 
just ~25 Euros - for me it's not worth taking that risk)

If you are referring to the 640G drive:
You have a copy of the original data on it, which is missing some 
(~300kByte) of Data.
The crucial point is the location of those gaps:
If you're lucky they were all in sectors which were located in the 
unused (empty) space of the filesystem - then you have not lost any data 
at all.
If you're less lucky, the gaps are in just a few files - worst case this 
will cause these affected files to become unreadable (e.g. if the file 
header got lost and can't be reconstructed from the remaining data). You 
can still have luck, if the affected files are e.g. your page or 
hibernation file.
If you're really unlucky, the gaps are in the blocks used to store the 
filesystem structure itself (e.g. the master file table for NTFS) - this 
would be kind of the worst case scenario, as you might a large amount of 
data (or would need to spend a lot of work with special tools to recover 
the data. R-Studio NTFS / FAT might be a good start in that situation, 
yet maybe a bit expensive for individuals...)

You'll have to find out how lucky you are :-/

There's just one important thing I would recommend you to do before you 
run any tool on the data on the 640G:
=> Create another copy first!
(And keep this copy until you have confirmed that you have recovered all 
data you need.)

If your tool (e.g. chkdsk) fails to recover the data correctly it will 
probably cause some major data loss on the data recovered from the 
broken dive. You won't have a second try if you don't have an 
"unmodified" copy left (which you could copy back over the failed 
recovery attempt as many times as you need).

From my experience especially with chkdsk you might run into a lot of 
"fun" if there's damage to the filesystem structure.
So make sure you got another copy.

Kind Regards
Felix