* sorry my / disk is under lvm
check the below KB its usefull for increase the size of vmdk
i was done this for one of vm under ESX4.1i
VMware KB: Increasing the size of a virtual disk
1. shutdown the VMmachine
2.edit the vmsettings
3.increase the vmdisk size
4. boot the vm create the new slice
5.extend the vg then lvextend