[Element name] LogicalDiskSizeInGB [Description] 
Optional. Specifies the size, in GB, of an empty disk to be attached to the Virtual Machine. If the disk that is being added is already registered in the subscription, this element is ignored. If the disk and VHD is being created by Azure as it is added, this element defines the size of the new disk. The number of disks that can be added to a Virtual Machine is limited by the size of the machine. For more information, see Virtual Machine and Cloud Service Sizes for Azure. This element is used with the MediaLink element.