This is the commands to backup the whole disk and to restore it back.
dd if=/dev/hda1 bs=1k conv=sync,noerror gzip -c ssh -c blowfish user@hostname "dd of=filename.gz bs=1k"
dd if=filename.gz ssh -c blowfish root@deadhost "gunzip -c dd of=/dev/hda1 bs=1k"
The backup command is done from machine where the backup file is located, not from the target machine we want to restore to.
For more detail, see the following: