func GetTotalCapacity(diskInfo []madmin.Disk) (capacity uint64) {
	for _, disk := range diskInfo {
		capacity += disk.TotalSpace
	}
	return capacity
}

// GetTotalUsableCapacity gets the total usable capacity in the cluster.
func GetTotalUsableCapacity(diskInfo []madmin.Disk, s StorageInfo) (capacity uint64) {
	for _, disk := range diskInfo {
		// Ignore invalid.

		prometheus.NewDesc(
			prometheus.BuildFQName(minioNamespace, "capacity_usable", "total"),
			"Total usable capacity online in current MinIO server instance",
			nil, nil),
		prometheus.GaugeValue,
		float64(GetTotalUsableCapacity(server.Disks, sinfo)),
	)

	// Report total usable capacity free
	ch <- prometheus.MustNewConstMetric(
		prometheus.NewDesc(
			prometheus.BuildFQName(minioNamespace, "capacity_usable_free", "total"),

	}
	if idx+1 > len(z.serverPools) {
		return pi, errInvalidArgument
	}

	info := z.serverPools[idx].StorageInfo(context.Background())
	info.Backend = z.BackendInfo()

	usableTotal := int64(GetTotalUsableCapacity(info.Disks, info))
	usableFree := int64(GetTotalUsableCapacityFree(info.Disks, info))
	return poolSpaceInfo{
		Total: usableTotal,
		Free:  usableFree,
		Used:  usableTotal - usableFree,
	}, nil

		return
	}

	// Get capacity info when asked.
	if r.Form.Get("capacity") == "true" {
		sinfo := objectAPI.StorageInfo(ctx, false)
		dataUsageInfo.TotalCapacity = GetTotalUsableCapacity(sinfo.Disks, sinfo)
		dataUsageInfo.TotalFreeCapacity = GetTotalUsableCapacityFree(sinfo.Disks, sinfo)
		if dataUsageInfo.TotalCapacity > dataUsageInfo.TotalFreeCapacity {

			Value:       float64(GetTotalCapacityFree(storageInfo.Disks)),
		})

		metrics = append(metrics, MetricV2{
			Description: getClusterCapacityUsageBytesMD(),
			Value:       float64(GetTotalUsableCapacity(storageInfo.Disks, storageInfo)),
		})

		metrics = append(metrics, MetricV2{
			Description: getClusterCapacityUsageFreeBytesMD(),