Re: [Bug-ddrescue] Problem using ddrescue

[Felix Ehlermann]

Dear Timothy,

some USB-bridges are not very suitable for recovering a failing drive.
In addition to the limited power supply available for bus powered devices
there are also issues with possibly poor error handling done by the bridge.
If possible you should try to connect the drive via sata directly.

Does the drive make any sounds (at startup, while running, when you try to
access it)?

Are any messages referring to sdb or usb in general being logged to dmesg,
/var/log/syslog, /var/log/messages, etc.?

Also I noticed that you apparently are not using a log file.
This is not recommended.
Did you read the manual? If your data is important it's really worth
spending the time to read it completely.

Also if you have sufficient storage I would recommend to recover to an image
file first.
At a later time you will probably start using other tools to access the data
in the recovered image - make sure to use these tools on a copy of your
image, so you don’t suffer additional data loss because the "repair"
activity of some other tool (e.g. a file system check) causes damage to your
image file.
If you must use a device as destination for recovery make sure that it has
been zeroed before you use it. This is especially important if you do not
use a log file (which would allow you to zero out the unreadable areas at a
later time).


Kind Regards
Felix Ehlermann


-----Ursprüngliche Nachricht-----
Von: address@hidden
[mailto:address@hidden Im Auftrag von Tim
Johnson
Gesendet: Mittwoch, 29. Oktober 2014 15:29
An: address@hidden
Betreff: [Bug-ddrescue] Problem using ddrescue

I am using ddrescue v 1.17 to try and recover a disk that seems to have 
had its partition table corrupted.

The disk is a 1T Seagate s/n NA4AHSB6 usb 3.0

I have tried running ddrescue to copy the disk onto a backup, both 
disk-to-disk and  disk-to-image, but it fails to do anything.  I can see 
the device with the command "ls /dev/sdb" ( confirmed by dmesg) but it 
does not appear in fdisk

I have run:

ddrescue -v -v -v -v -f -n /dev/sdb /dev/sdc 
/home/timj/Desktop/ddrescue.log:  no messages, no logfile created and ps 
-ax reports no time spent running ddrescue

ddrescue -v -v -v -v -f -n /dev/sdb /dev/sdc 
/media/timj/iomega/seagate.img 
/home/timj/Desktop/ddrescue.log/ddrescue.log: no messages, no image 
file, no logfile created and ps -ax reports no time spent running ddrescue


ddrescue -v -v -v -v -f -n -R  /dev/sdb /dev/sdc 
/media/timj/iomega/seagate.img 
/home/timj/Desktop/ddrescue.log/ddrescue.log: no messages, no image 
file, no logfile created and ps -ax reports no time spent running ddrescue

Any advice or is the disk long gone?

-- 
Dr Timothy Johnson
Department of Actuarial Mathematics and Statistics
and the Maxwell Institute for Mathematical Sciences,
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh EH14 4AS
UK

tel:    +44 (0) 131 451 8343
fax:    +44 (0) 131 451 3249

http://www.ma.hw.ac.uk/~timj/


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