driveOfflineCountMD = NewGaugeMD(driveOfflineCount,
		"Count of offline drives")
	driveOnlineCountMD = NewGaugeMD(driveOnlineCount,
		"Count of online drives")
	driveCountMD = NewGaugeMD(driveCount,
		"Count of all drives")

	// iostat related
	driveReadsPerSecMD = NewGaugeMD(driveReadsPerSec,
		"Reads per second on a drive",
		allDriveLabels...)
	driveReadsKBPerSecMD = NewGaugeMD(driveReadsKBPerSec,

)

var (
	usageSinceLastUpdateSecondsMD = NewGaugeMD(usageSinceLastUpdateSeconds,
		"Time since last update of usage metrics in seconds")
	usageTotalBytesMD = NewGaugeMD(usageTotalBytes,
		"Total cluster usage in bytes")
	usageObjectsCountMD = NewGaugeMD(usageObjectsCount,
		"Total cluster objects count")
	usageVersionsCountMD = NewGaugeMD(usageVersionsCount,

var (
	bucketReplLastHrFailedBytesMD = NewGaugeMD(bucketReplLastHrFailedBytes,
		"Total number of bytes failed at least once to replicate in the last hour on a bucket",
		bucketL, targetArnL)
	bucketReplLastHrFailedCountMD = NewGaugeMD(bucketReplLastHrFailedCount,
		"Total number of objects which failed replication in the last hour on a bucket",
		bucketL, targetArnL)
	bucketReplLastMinFailedBytesMD = NewGaugeMD(bucketReplLastMinFailedBytes,

	return MetricDescriptor{
		Name:           name,
		Type:           CounterMT,
		Help:           help,
		VariableLabels: labels,
	}
}

// NewGaugeMD - creates a new gauge metric descriptor.
func NewGaugeMD(name MetricName, help string, labels ...string) MetricDescriptor {
	return MetricDescriptor{
		Name:           name,
		Type:           GaugeMT,
		Help:           help,