dd usage :  save raw image and restore raw image.

Can be used for backup or Cloingthe harddrivers or usb keys.

1 – Check who is who :

With command :   

df –h

in our case :

sdb1 = disk1
sdc1 = disk2

or use gparted :

To save full raw disk image

This method compress the image : if you use only the command dd – the image size will be 2GB While with gzip image size is 2mb (for my test I have used only 1 small image.png)

sudo dd if=/dev/sda conv=sync,noerror bs=64k status=progress | gzip -c > /media/dimm/data/image.raw

The above command just cloned the entire hard disk, including the MBR, bootloader, all partitions, UUIDs, and data.

To restore full raw image

Warning do this only from live CD

 sudo gunzip -c /media/dimm/disk2/image.raw | dd of=/dev/sdb1 status=progress

After restore operation , unmount /mount hd to see the disk changes.

dd mac usage save raw image and restore raw image

• if ==>input file
• of ==>output file
• Detect DISKS :   df -h
• unmount our src : diskutil unmountDisk /dev/disk3

back up cmd : time : 6500 seconds @ 120 GB
our SRC is /dev/disk3 our dest is : /Volumes/extern/backup.img

cmd Backup ==> dd if=/dev/disk3 of=/Volumes/extern/backup.img bs=512 status=progress
cmd Restore ==> dd if=/Volumes/extern/backup.img of=/dev/disk3 bs=512 status=progress