// and sends to given channel
func storageMetricsPrometheus(ch chan<- prometheus.Metric) {
	objLayer := newObjectLayerFn()
	// Service not initialized yet
	if objLayer == nil {
		return
	}

	server := getLocalServerProperty(globalEndpoints, &http.Request{
		Host: globalLocalNodeName,
	}, true)

	onlineDisks, offlineDisks := getOnlineOfflineDisksStats(server.Disks)
	totalDisks := offlineDisks.Merge(onlineDisks)