Full hard disk copy:
dd if=/dev/hdx of=/dev/hdy dd if=/dev/hdx of=/path/to/image dd if=/dev/hdx | gzip > /path/to/image.gz
Hdx could be hda, hdb etc. In the second example gzip is used to compress the image if it is really just a backup.
Restore Backup of hard disk copy:
dd if=/path/to/image of=/dev/hdx gzip -dc /path/to/image.gz | dd of=/dev/hdx
In order to backup only the first few bytes containing the MBR and the partition table you can use dd as well.
dd if=/dev/hdx of=/path/to/image count=1 bs=512
dd if=/path/to/image of=/dev/hdx
Add “count=1 bs=446″ to exclude the partition table from being written to disk. You can manually restore the table.