A FlexClone volume inherits its initial space guarantee from its parent volume. For example, if you create a FlexClone volume from a parent volume with a space guarantee of volume, then the FlexClone volume's initial space guarantee will be volume also. You can change the FlexClone volume's space guarantee.
For example, suppose that you have a 100-MB FlexVol volume with a space guarantee of volume, with 70 MB used and 30 MB free, and you use that FlexVol volume as a parent volume for a new FlexClone volume. The new FlexClone volume has an initial space guarantee of volume, but it does not require a full 100 MB of space from the aggregate, as it would if you had copied the volume. Instead, the aggregate needs to allocate only 30 MB (100 MB minus 70 MB) of free space to the clone.
If you have multiple clones with the same parent volume and a space guarantee of volume, they all share the same shared parent space with each other, so the space savings are even greater.