[svlug] Failing external drive. Planning to DD the failing drive to new external drive. Help please
eager at eagercon.com
Thu Nov 12 17:17:34 PST 2015
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On 11/12/2015 10:15 AM, H P Ladds wrote:
> On Thu, Nov 12, 2015 at 11:26 AM, Michael Eager <eager at eagercon.com <mailto:eager at eagercon.com>> wrote:
> On 11/12/2015 07:44 AM, H P Ladds wrote:
> > I have an external hard drive failing and hope to DD the drive to a new external hard drive.
> You should not use dd to copy data from one disk partition to another.
> Use rsync, cpio, tar, or cp.
> > Should I reformat the new drive to ext3 (or ext4) before DDing?
> Assuming that the new drive is identical to the old drive,
> however you format the partition on new drive, when you copy the old
> partition to the new one using dd, the format will be replaced
> by the format of the partition on the old drive. In fact, there is
> no need to format the drive when you use dd to copy a partition.
> (But, as I said, don't use dd.)
> > The failing drive has two 500 gig partitions (I believe ext3). Should I DD the partitions separately
> > or DD the entire drive?
> Using dd to copy from one disk to a disk with a different size or
> organization is unlikely to work. At best, you will lose space.
> At worst, the drive will be unmountable.
> So true...
> Partitioning the new hard drive with two 600G partitions, not formatting the partitions and then...
> dd if=/dev/sdh3 of=/dev/sdi2
> resulted in an umountable drive /dev/sdi2
> "wrong fs type, bad option, bad superblock on /dev/sdi2,
> missing codepage or helper program, or other error
> In some cases useful info is found in syslog - try
> dmesg | tail or so"
> > After DDing I'll try to retrieve the data. Oh and it is all data, no OS.
> If you want to use dd, you can create an image of the failing drive on
> a spare drive, mount the image using the loopback device, and copy from the
> image to your final destination using rsync. This is sometimes useful if
> the old drive is failing, so you have to make multiple copies using dd.
> Michael Eager eager at eagercon.com <mailto:eager at eagercon.com>
> 1960 Park Blvd., Palo Alto, CA 94306 650-325-8077 <tel:650-325-8077>
> svlug mailing list
> svlug at lists.svlug.org <mailto:svlug at lists.svlug.org>
Michael Eager eager at eagercon.com
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077
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