    # File lib/fog/ecloud/models/compute/server.rb, line 162
            def add_disk(size)
              index = disks.map { |d| d[:Index].to_i }.sort[-1] + 1
              vm_disks = disks << {:Index => index.to_s, :Size=>{:Unit => "GB", :Value => size.to_s}, :Name => "Hard Disk #{index + 1}"}
              data = service.virtual_machine_edit_hardware_configuration(href + "/hardwareConfiguration", _configuration_data(:disks => vm_disks)).body
              task = self.service.tasks.new(data)
            end