func GetTotalCapacityFree(diskInfo []madmin.Disk) (capacity uint64) {
	for _, d := range diskInfo {
		capacity += d.AvailableSpace
	}
	return
}

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

	m.Set(healthCapacityUsableTotalBytes, float64(GetTotalUsableCapacity(storageInfo.Disks, storageInfo)))
	m.Set(healthCapacityUsableFreeBytes, float64(GetTotalUsableCapacityFree(storageInfo.Disks, storageInfo)))

	return nil

		prometheus.NewDesc(
			prometheus.BuildFQName(minioNamespace, "capacity_usable_free", "total"),
			"Total free usable capacity online in the cluster",
			nil, nil),
		prometheus.GaugeValue,
		float64(GetTotalUsableCapacityFree(server.Disks, sinfo)),
	)

	// MinIO Offline Disks per node
	ch <- prometheus.MustNewConstMetric(
		prometheus.NewDesc(
			prometheus.BuildFQName(minioNamespace, "disks", "offline"),

	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 {
			dataUsageInfo.TotalUsedCapacity = dataUsageInfo.TotalCapacity - dataUsageInfo.TotalFreeCapacity
		}
	}

	}

	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
}

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

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

		metrics = append(metrics, MetricV2{
			Description: getClusterDrivesOfflineTotalMD(),
			Value:       float64(offlineDrives.Sum()),
		})