Re: [libvirt] [virt-tools-list] difference between blkid of a system and uuid of virtual machine by virt-manager

I want to know what is the difference between the output blkid command shows and the uuid which is set by virt-manager while creating a guest. Suppose in case of a re installation sort of situation I want to do a fresh install and restore things from a backup then where does this UUID thing comes into picture and what is its role with respect to Virtual Machines.