i just cleaned a 50GB partition with
dd if=/dev/zero of=/dev/sda1
then added some data to it (actually installed a linux distro) some 3Gb on ext4.
and decided to make a image.
dd if=/dev/sda1 | gzip -9 > sda1.dd.gz
and to my surprise, that file has 45GB!
my thinking would be that the this file would have some 4GB as most of the size would be tailing zeros that
gzip would take care of.
where am I wrong? anyway to check how back the fragmentation is after the add-data step?
Also, if it is fragmentation, any way to fix it? i'm now writing /dev/zero to a file until the drive is full...