Hi!

There is an RFE being implemented currently (https://bugzilla.redhat.com/show_bug.cgi?id=734120) to use --inplace option in virt-sparsify to sparsify a disk image in-place, without copying it.

The problem is that in-place sparsify works on NFS only starting from NFS 4.2, while the copying implementation supposedly works with any storage.

From my point of view, it is better to remove the old code and start with the new code that uses --inplace and just add to document that one will need NFS >= 4.2 for sparsify feature to work. Although the old implementation exists, it is not used currently so there are no actual users that may be affected by the change. If it will be a crying need to use sparsify on older NFS or some other incompatible storage, we can add it later on the base of the new code. The old code is far from ideal and we will need to rewrite it in any case, and there is not sense to do this without real need.