practically the same situation. Can add that simple operation with rapid clone takes to much time. 40 GB VM about 4.5 hours.
don't think it is network, because all operations like this, or at least in our case via VSC usually are done locally on the filer.
Vmware 5, 2240-4, 8.1 7mode, NFS, VSC 4.0
during VSC restoration on Vshere all nfs storages become inactive/unmounted, waited several hours, had to restart filer, and clear restore task.
Created case. There are several situation on forums but with older systems and VSC 2.x.x. the only solution was to upgrade VSC
As I understand operations via VSC like:
rapid clone on the same filer
restore
backup
are using benefits from WAFL and take only minutes to be done.
seems VSC has some problems