[svlug] Failing external drive. Planning to DD the failing drive to new external drive. Help please

Steve Litt slitt at troubleshooters.com
Thu Nov 12 09:29:37 PST 2015

On Thu, 12 Nov 2015 10:44:46 -0500
H P Ladds <householdwords at gmail.com> wrote:

> I have an external hard drive failing and hope to DD the drive to a
> new external hard drive.

I'd suggest using ddrescue instead. It's available on System Rescue CD.

When doing ddrescue, use the log file as described in the docs, and use
a low number for retries so it doesn't take a week to complete. If
you're dealing with damaged data, a time of 24 hours to copy an entire
disk wouldn't surprise me a bit.

> Should I reformat the new drive to ext3 (or ext4) before DDing?

No need. You might want to test the new drive to make sure it's good.

> The failing drive has two 500 gig partitions (I believe ext3). Should
> I DD the partitions separately or DD the entire drive?

Unless you have reason to believe that one of the partitions is more
damaged than the other, I'd start by doing the whole drive. That way
you don't need to partition your disk. It would be much easier and less
prone to human error.


Steve Litt 
November 2015 featured book: Troubleshooting Techniques
     of the Successful Technologist

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