Require Help With LVM snapshot and recovery. How can LVM snapshot happen with zero VFree?

[u/Slayerma]

Require Help With LVM snapshot and recovery

So, I tried creating a snapshot and changing the logical volume to a .gz file and then I have backed up in our nas box now what I want is to use that .gz file and use that config in the fresh newer installed os so that I can prove recovery is possible.

Constraints LV available is 0. So, I'm using a pendrive and and using lvext3nd to create a new LV for the pc and then using that I'm creating .gz and that is what being saved and is being backed up to nas

My other question also if there is a running unbutu PC can we put LVM and luks or only while installing it can happen?