// values for IOStat related disk metrics e.g. reads/sec.
		prevDriveIOStats            map[string]madmin.DiskIOStats
		prevDriveIOStatsMu          sync.RWMutex
		prevDriveIOStatsRefreshedAt time.Time
	)

	loadDriveMetrics := func(ctx context.Context) (v storageMetrics, err error) {
		objLayer := newObjectLayerFn()
		if objLayer == nil {
			return
		}

		storageInfo := objLayer.LocalStorageInfo(GlobalContext, true)

	if ioStats.writesPerSec > 0 {
		m.Set(driveWritesAwait, ioStats.writesAwait, labels...)
	}

	m.Set(drivePercUtil, ioStats.percUtil, labels...)
}

// loadDriveMetrics - `MetricsLoaderFn` for node drive metrics.
func loadDriveMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
	driveMetrics, err := c.driveMetrics.Get()
	if err != nil {
		metricsLogIf(ctx, err)
		return nil
	}

			// iostat related
			driveReadsPerSecMD,
			driveReadsKBPerSecMD,
			driveReadsAwaitMD,
			driveWritesPerSecMD,
			driveWritesKBPerSecMD,
			driveWritesAwaitMD,
			drivePercUtilMD,
		},
		loadDriveMetrics,
	)

	clusterHealthMG := NewMetricsGroup(clusterHealthCollectorPath,
		[]MetricDescriptor{
			healthDrivesOfflineCountMD,
			healthDrivesOnlineCountMD,
			healthDrivesCountMD,