Re: dd limit???

["Robert G. (Doc) Savage" <dsavage@peaknet.net>]

On Wed, 2011-06-08 at 08:56 -0400, Robert Citek wrote: 
> On Wed, Jun 8, 2011 at 6:36 AM, Robert G. (Doc) Savage
> <dsavage@peaknet.net> wrote:
> > I'm puzzled. I've never seen a raw utility failure like this. dd is a
> > standard forensic tool that's been used reliably for many years. This
> > application does a bit-by-bit copy of partitions and MBR for later bare
> > metal restoration, should the "yum update" method fail for F15.
> 
> Not likely a limitation of dd as I was able to create a 200 GB image using dd:
> 
[snip] 
> Is it possibly a limitation of the USB converter?  Or something
> defective in the drive?
> 

Robert,

I changed hosts yesterday morning. I plugged the drive with its USB
converter into my 64-bit F14 laptop, then launched dd on my way out the
door. I came home to find it stalled at 104,329,412,608 bytes. This time
dd died "properly" -- but at the same place:

# dd if=/dev/sdc2 of=F14-32-rootfs.img bs=2048
dd reading `/dev/sdc2`: Input/output error
50942096+0 records in
50942096+0 records out
104329412608 bytes (104 GB) copied, 3396.89 s, 30.7 MB/s

Last night I ran F14's e2fsck with the -c (check for bad blocks) option
against /dev/sdc2. (The ancient e2fsck in RHEL5 refused to run against
that partition at all, suggesting a possible bad superblock.) Sure
enough, it found something near the end of the partition:

/dev/sdc2: Updating bad block node
...
/dev/sdc2: ***** FILE SYSTEM WAS MODIFIED *****

To be safe, I ran "dd_rescue /dev/sdc2 F14-32-rootfs.img". It stumbled
at the 88% point -- probably in the same pothole e2fsck -c ran into, but
this time it was able to recover and complete a full image.

After all that work, when I plugged it back into its original Thinkpad
host the drive booted thru GRUB phase 1 but no farther. Hopefully a
rescue disk can repair it so I can continue the upgrade.

--Doc

P.S. Yes, I'm looking for a replacement EIDE notebook drive 120GB or
larger. I've found a new WD 320GB Scorpio Blue EIDE drive for about
$100.


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