[ashmud]

VMware supports "parent" vmdk files. The leaf-node "child" vmdk will diff based on the ancestors. VMware Player does support this. The VMware implementation of XPMode uses it. You can use vdiskmanager to convert the root vmdk to sparse files, which leaves the main vmdk file with just the configuration in it. This makes it much easier to set up the parent-child relationship than monolithic vmdk.