    # File lib/fog/ecloud/models/compute/server.rb, line 173
            def add_disk(size)
              index = disks.map { |d| d[:Index].to_i }.sort[-1] + 1
              vm_disks = disks << {:Index => index, :Size=>{:Unit => "GB", :Value => size}}
              data = connection.virtual_machine_edit_hardware_configuration(href + "/hardwareConfiguration", _configuration_data(:disks => vm_disks)).body
              task = Fog::Compute::Ecloud::Tasks.new(:connection => connection, :href => data[:href])[0]
            end