By default, the datastore hard disks feature is enabled for the platform and the cloud administrator user only. This feature creates non-persistent hard disks on the hypervisor datastore. When the user undeploys the VM or detaches the hard disk the platform will destroy the data on the hard disk.
To use this feature, go to Virtual datacenters → open Virtual appliance → Virtual machines → edit virtual machine → Storage → add → select Assign virtual disk.
To disable the option to create a hard disk when configuring a VM, go to Configuration → General → Edit → deselect Show virtual machine hard disk tab option.
To enable other users to add, edit and remove disks, assign the "Manage virtual machine hard disks" privilege.
By default, the standard user that can configure a VM will be allowed to modify existing disks, for example, to resize them, even if they do not have the privilege to manage hard disks.