If I may have a more general question on how to back up my system. After weeks of getting my system on Ubuntu 18.04 up and running, I am increasingly worried that I could accidentally ruin the installation.

I have a mini PC, the operating system is on a eMMC kind of drive. On top, I plugged on a ssd drive with 64 GB which in theory I could also use to save the back up.

What is the safest way to create a back up, from which I can restore the system as it is? For the Pi I was simply creating an image for the sd card, but I am not sure how that works for a pc?

Best, Helge