I recently wanted to rename a vmdk on an ESX4 box. This wasn’t part of a cluster and there were no VC’s in the environment (hence the Storage vMotion trick couldn’t be used). The easiest and safest way to perform the rename is to SSH to the ESX box and use the following command:
There are many other switches that can be used with the vmkfstools command. One of the more useful ones is -i used for cloning a vmdk. The -d switch can also be added to specify the type of disk (thick, thin, RDM etc).