There are some options for clone disk for other platform like oVirt.   

--clonetype [thin|full]

                        A thin clone uses copy-on-write (COW) reflinked clone meaning it is dependent on the base template, but enables rapid cloning.

                        Full clone will make a full physical copy hence not be dependent on the base template.

Thin clone uses less space and will not be as performant as full clone, especially under heavy write workloads.

                        By default a thin clone is created, great for testing; should be avoided in production environments.

I want to know which type is oVirt using when we clone vm from template ?