There are multiple way to de this. The easiest solution would be to une a second disk with same size or bigger and clone the current one onto the new one, using dd or clonezilla

if you have enough size on your dis_ for a second root partition, you can use dd to clone the existing root partition in the new one, edit /etc/fstab on the new one to point to the correct root partition, and us grub-mkconfig if you use grub, use grub-mkconfig to reconfigure it. It should automatically detect the new partition.