Maybe I am blind and cannot read well, also, I am pretty sure I've opened a bug on this subject already, but cannot find now.
But - I could not find anywhere in 3.4 docs (Admin/Tech) where do we explain how to increase the size of current storage domain in RHEV.
Details are in this solution:
Topics added to publication spec:
Increasing NFS Storage
Increasing iSCSI or FCP Storage
Revision History updated.