On Sunday 22 Jul 2012 18:45:50 Alex Schuster wrote:
> Jarry writes:
> > I want to backup my whole hard-drive (8 partitions) with:
> > # dd if=/dev/sda | gzip > /path/image.gz
> > 
> > In order to achieve good compression level I'd like to wipe
> > out all empty space with zeros. How can I do that?
> 
> You can create files containing only zeros on all partitions until
> they are full. Like this:
> 
> for i in 5 6 7 8 9 10 11 12
> do
> 	mount /dev/sda$i /mnt
> 	dd if=/dev/zero of=/mnt/zero
> 	rm /mnt/zero
> 	umount /mnt
> done
> 
> 	Wonko

Only to add that using bs=4096 or bs=2048 would help this take less than a 
week waiting for it to finish.  :-)
-- 
Regards,
Mick