Expanding a VMFS
One of the better new features of vSphere was online expansion of VMFS’s. Unlike previous version of VMware you now no longer need to use extents and if a LUN which a VMFS resides on has free space you can expand the VMFS online.
Simple select the Datastore and select expand.
Once expanded you can then increase the vmdk file size when you power off the VM, reboot the VM and use dispart to expand the partition to the new size of the vmdk file.