2 TB external HD does not mount any more. How to save it's data?

iceblink iceblink at seti.nl
Tue Dec 16 16:24:37 UTC 2014

On 2014-12-16 17:08, Bas G. Roufs wrote:
>> Actually, it needs to be discarded -
> You mean: I need NOT to use it any more apart from an attempt to
> recover the data?

Indeed. Think of it like a tyre on your bicycle. It wears out, slowly 
but surely. By the time you notice defects on it and start to see the 
canvas, you have already used it for too long. You could try and create 
a new profile on it by carving what is left of the rubber (i.e. reformat 
the disk) but that is an accident waiting to happen.

>> with luck you will be able to get
>> your data off it first. Next time this happens, start recovering the
>> data as soon as the disk shows the first signs, however small, of
>> impending failure.
>> You'll probably have to use something that can read the device
> directly
>> - I suggest you take an image copy using something like dd (which
> can
>> optionally ignore error) then work on the copy.
> The above answer makes sense. The paragraph 'Imaging a damaged device,
> filesystem or drive' at help.ubuntu.com/community/DataRecovery points
> in the same direction. However, this brings up a next question: to
> what device can I copy an image of a failing external HD of 2 TB? From
> that device, 50% or 1 GB has been in use. My HD at the laptop is out
> of the question - that one is 350 GB. So, I will need to buy another
> external HD to which I can copy the image. How big should that one
> need to be? 2 TB as well? Or better 3 TB?

Because you will be making an identical copy, bit by bit (without 
knowing where the data is located), it needs to be 2TB or larger.

The idea is to minimise the use of the failing disk, because that will 
only cause more defects. So make a bit-by-bit digital copy to a new 
disk, and then use the new disk to try and save the data.

Best regards,

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