I would like to backup my disk, I'm using only 24GB, but the full partition size 255GB. I would like to backup the whole system to an 32GB Flash Drive, just in case if the system it's not working, I still can boot from the USB Stick, How can I do that? In this case is dd
a good option?
To install it Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command below.
1Source:Debian Admin
Based on the new information that you supplied, you can use Remastersys. Remastersys will backup your install to ISO. Then you can use the outcome to make a Live CD/USB which can be used to install the backup to disk.
Or you can use dd to clone the original disk to USB stick but you need a big enough USB drive so the backup will fit.
Another option is to use Clonezilla. Clonezilla is an Open Source Software for Disk Imaging and Cloning, similar to ghost. You can get it by Clicking Here.