FYI - Just thought I'd post what we just discovered as I haven't seen it
here yet.

By default, VMware ESX 3.51 formats a Datastore with a 1 MB block size.

This creates a 256GB maximum size limitation of a single Hard Disk that
can be added to a virtual server (at least for a Netware 6.x VM). So,
if you plan to grow a Hard Disk beyond 256GB, make sure you format your
Datastore with a larger block size...