apiRequestsTotalMD = NewCounterMD(apiRequestsTotal,
		"Total number of requests", "name", "type")
	apiRequestsErrorsTotalMD = NewCounterMD(apiRequestsErrorsTotal,
		"Total number of requests with (4xx and 5xx) errors", "name", "type")
	apiRequests5xxErrorsTotalMD = NewCounterMD(apiRequests5xxErrorsTotal,
		"Total number of requests with 5xx errors", "name", "type")
	apiRequests4xxErrorsTotalMD = NewCounterMD(apiRequests4xxErrorsTotal,

	bucketReplProxiedDeleteTaggingRequestsTotalMD = NewCounterMD(bucketReplProxiedDeleteTaggingRequestsTotal,
		"Number of DELETE tagging requests proxied to replication target",
		bucketL)
	bucketReplProxiedGetRequestsFailuresMD = NewCounterMD(bucketReplProxiedGetRequestsFailures,
		"Number of failures in GET requests proxied to replication target",
		bucketL)
	bucketReplProxiedGetRequestsTotalMD = NewCounterMD(bucketReplProxiedGetRequestsTotal,

	processIOReadBytesMD              = NewCounterMD(processIOReadBytes, "Total bytes read by the process from the underlying storage system, /proc/[pid]/io read_bytes")
	processIOWCharBytesMD             = NewCounterMD(processIOWCharBytes, "Total bytes written by the process to the underlying storage system including page cache, /proc/[pid]/io wchar")

	ilmTransitionPendingTasksMD         = NewGaugeMD(transitionPendingTasks, "Number of pending ILM transition tasks in the queue")
	ilmTransitionMissedImmediateTasksMD = NewCounterMD(transitionMissedImmediateTasks, "Number of missed immediate ILM transition tasks")
	ilmVersionsScannedMD                = NewCounterMD(versionsScanned, "Total number of object versions checked for ILM actions since server start")
)

// loadILMMetrics - `MetricsLoaderFn` for ILM metrics.

	return prometheus.NewDesc(
		md.toPromName(namePrefix),
		md.Help,
		md.VariableLabels, extraLabels,
	)
}

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