 
           SR_type: get('type')
 
-          physical_usage: get('physical_utilization')
-
-          usage: get('virtual_allocation')
-
-          size: get('physical_size')
+          physical_usage: number get 'physical_utilization'
+
+          usage: number get 'virtual_allocation'
+
+          size: number get 'physical_size'
 
           $container: null # TODO
 

          # TODO: `0` should not be used when the value is unknown.
          memory: @dynamic {
            usage: null
            size: get 'memory_dynamic_min'
          }, {
            VM_metrics: {
              update: (metrics, UUID) ->


      helper value

  number = (fn) ->
    (args...) -> +(fn.apply this, args)

  ->
    key: (value, key) -> value.uuid ? key

