Re: [Bug-ddrescue] help needed recovering a hard drive with bad blocks

[Ariel]

On Thu, 19 Apr 2007, gr wrote:

> One thing I noticed when booting up Knoppix is that
> the bad hard drive takes a long time to be "detected"
> during the bootup.  When the kernel is scanning for
> partitions and creating /etc/fstab it just hangs there
> for about 5 minutes and I can hear the drive siliently
> clicking (clicks about every second).  I'm worried
> that the drive may be *really* slow .... but
> eventually it does boot up and I can see that Knoppix
> has detected the partition.  I have a feeling that the
> Volume Boot Record has been affected by the bad
> sectors though...

Knoppix is trying to figure what kind of filesystem the drive has, it's 
not a good sign that it's taking so long. Don't waste any time - get 
started with ddrescue as soon as possible because a: the drive could get 
worse, and b: it can take a LONG time - depending on how much bad data 
there is. (You could get lucky, and it's just one section of the drive.)

Even a slightly bad drive can take a few _days_ to copy.

> > I'm assuming the old drive is just one large
> > partition.
>
> Yes, it was just one large NTFS partition ... about
> 114  GB large ... about 112 GB of it personal data.
>
>
> > If you have enough space on the new drive for 2
> > partitions exactly the
> > same size as the one on the bad drive do it, the
> > extra one will be useful.
>
> Well I did buy a 320 GB hard drive, so I could make
> two identical 114 GB partitions ... but I don't need
> to format these partitions as NTFS, right? ... I can
> just use ddrescue to image to the unformatted space
> directly, right?

A "formatting" of a drive is just writing the filesystem headers and 
stuff, it doesn't do anything to the drive, if you copied over it (as you 
are going to do) you will just write something else there.

(Back in the "olden days" there was something called low level formatting, 
you don't do that anymore though. Also used to be when you formatted a 
drive it wrote zeros to all the unused sections, today the program 
doesn't bother: "quick format" it just writes the data it needs.)

You do need to partition is though, and make sure to set the partition 
type correctly.

You might consider adding a third partition in the rest of the drive. Use 
the space for the logfiles, and any other scratch data. (USB flash drives 
can wear out if you use them for logfiles, since they have a limited 
number of writes, and each write of the logfile is tiny, but counts as a 
full write. Typically you get 100,000 to 1 million writes, and a logfile 
written every 5 seconds for 2 days is 34,000 writes.)

        -Ariel