At some point you may find it necessary to expand an array or LUN. ESXi 4.0 introduces a feature called volume grow. ESXi 3.5 lacks this feature you either have to migrate your VMs and then recreate your datastore, or expand it with an extent as shown below.
Volume Grow with ESXi 4.0
Expand a datastore with ESXi 3.5
Copyright © 2011 - Dave Mishchenko