In earlier versions to 3.5, when specifying the size of a new virtual disk, I had an opportunity to decide to allocate the entire space,
In this version (ESX 3.5), this option does not appear
ESX V3.0 and above always allocate the complete disk space on vmfs3 volumes (can't tell you how esx2.x did it). Only possibility to use thin provisioning is using NFS.
There are 10 types of people. Those who understand binary and the rest.