I can see partitions but not even one harddisk.
How can I see my harddisks and clone them?
Gdiskdump shows you have three HDDs: sdb, sdc, sdd.
also try gparted and parted.
To clone a drive and all partitions, including MBR or GPT:
BE CAREFUL with dd! You can easily make a mistake.
make sure its unmounted ( like when using a liveusb)
dd if=/dev/<device> of=filename.you.choose
To get a specific partition:
dd if=/dev/sdxn of=filename where sdxn is something like sdb1 or sdc6
to restore:
dd if=your.filename of=/dev/device[partition#] ( e.g. /dev/sdb3)