ddrescue
"GNU ddrescue - Data recovery tool. Copies data from one file or block device to another, trying to rescue the good parts first in case of read errors." - man ddrescue
There are actually two tools called ddrescue: dd_rescue and gddrescue. gddrescue is the best.
- Software home page - http://www.gnu.org/software/ddrescue/
- Instruction Manual - http://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html
Examples
Attempt to mirror an entire hard disk
ddrescue -f -n --min-read-rate=500000 /dev/source_disk /dev/target_disk ~/ddrescue.log
This uses the minimum read rate to skip sctors that may be bad on the input device.
Wipe a hard disk and log bad sectors
sudo ddrescue --force /dev/zero /dev/disk/by-id/ata-foo ~/ddrescue-ata-foo.log
You can re-run this exact same command to resume the wipe of a hard disk.
Attempt to continue the mirror of a hard disk
ddrescue -f -n -A /dev/source_disk /dev/target_disk ~/ddrescue.log
Wipe the good sectors of a failing disk
This requires a valid rescue log file mapping out the good sectors that were recovered.
ddrescue --fill=+ --force /dev/zero /dev/bad_drive ~/bad_drive_wipe.log