diff --git a/enhanced/metrics.go b/enhanced/metrics.go
index c62b29cd..cf62f930 100644
--- a/enhanced/metrics.go
+++ b/enhanced/metrics.go
@@ -11,6 +11,27 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 )
 
+var (
+	diskRead = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "node",
+			Subsystem: "disk",
+			Name:      "read_bytes_total",
+			Help:      "The total number of bytes read successfully.",
+		},
+		[]string{"region", "instance", "device"},
+	)
+	diskWritten = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "node",
+			Subsystem: "disk",
+			Name:      "written_bytes_total",
+			Help:      "The total number of bytes written successfully.",
+		},
+		[]string{"region", "instance", "device"},
+	)
+)
+
 // osMetrics represents available Enhanced Monitoring OS metrics from CloudWatch Logs.
 //
 // See https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_Monitoring.OS.html#USER_Monitoring.OS.CloudWatchLogs
@@ -265,19 +286,23 @@ func makeRDSDiskIOMetrics(s *diskIO, constLabels prometheus.Labels) []prometheus
 
 // makeNodeDiskMetrics returns node_exporter-like node_disk_ metrics.
 func makeNodeDiskMetrics(s *diskIO, constLabels prometheus.Labels) []prometheus.Metric {
-	// move device name to label
-	labelKeys := []string{"device"}
-	labelValues := []string{s.Device}
+	labels := make(prometheus.Labels, len(constLabels)+1)
+
+	for k, v := range constLabels {
+		labels[k] = v
+	}
+
+	labels["device"] = s.Device
 	res := make([]prometheus.Metric, 0, 2)
 
 	if s.ReadKb != nil {
-		desc := prometheus.NewDesc("node_disk_read_bytes_total", "The total number of bytes read successfully.", labelKeys, constLabels)
-		m := prometheus.MustNewConstMetric(desc, prometheus.CounterValue, float64(*s.ReadKb*1024), labelValues...)
+		m := diskRead.With(labels)
+		m.Add(float64(*s.ReadKb * 1024))
 		res = append(res, m)
 	}
 	if s.WriteKb != nil {
-		desc := prometheus.NewDesc("node_disk_written_bytes_total", "The total number of bytes written successfully.", labelKeys, constLabels)
-		m := prometheus.MustNewConstMetric(desc, prometheus.CounterValue, float64(*s.WriteKb*1024), labelValues...)
+		m := diskWritten.With(labels)
+		m.Add(float64(*s.WriteKb * 1024))
 		res = append(res, m)
 	}
 
diff --git a/enhanced/metrics_test.go b/enhanced/metrics_test.go
index a9182fda..c7a5e6cb 100644
--- a/enhanced/metrics_test.go
+++ b/enhanced/metrics_test.go
@@ -23,13 +23,21 @@ func TestParse(t *testing.T) {
 		t.Run(data.instance, func(t *testing.T) {
 			// Test that metrics created from fixed testdata JSON produce expected result.
 
-			m, err := parseOSMetrics(readTestDataJSON(t, data.instance), true)
+			d := readTestDataJSON(t, data.instance)
+
+			m, err := parseOSMetrics(d, true)
+			require.NoError(t, err)
+
+			m2, err := parseOSMetrics(d, true)
 			require.NoError(t, err)
 
 			actualMetrics := helpers.ReadMetrics(m.makePrometheusMetrics(data.region, nil))
 			sort.Slice(actualMetrics, func(i, j int) bool { return actualMetrics[i].Less(actualMetrics[j]) })
 			actualLines := helpers.Format(helpers.WriteMetrics(actualMetrics))
 
+			actualMetrics2 := helpers.ReadMetrics(m2.makePrometheusMetrics(data.region, nil))
+			sort.Slice(actualMetrics2, func(i, j int) bool { return actualMetrics2[i].Less(actualMetrics2[j]) })
+
 			if *goldenTXT {
 				writeTestDataMetrics(t, data.instance, actualLines)
 			}
@@ -41,6 +49,15 @@ func TestParse(t *testing.T) {
 			// compare both to try to avoid go-difflib bug
 			assert.Equal(t, expectedLines, actualLines)
 			assert.Equal(t, expectedMetrics, actualMetrics)
+
+			for i, v := range actualMetrics {
+				switch v.Name {
+				case "node_disk_read_bytes_total", "node_disk_written_bytes_total":
+					assert.Equal(t, 2*v.Value, actualMetrics2[i].Value)
+				default:
+					assert.Equal(t, v.Value, actualMetrics2[i].Value)
+				}
+			}
 		})
 	}
 }
diff --git a/enhanced/scraper.go b/enhanced/scraper.go
index e00d79f8..be4009a1 100644
--- a/enhanced/scraper.go
+++ b/enhanced/scraper.go
@@ -79,9 +79,10 @@ func (s *scraper) scrape(ctx context.Context) (map[string][]prometheus.Metric, m
 			l = l.With("IngestionTime", aws.MillisecondsTimeValue(event.IngestionTime).UTC())
 
 			var instance *sessions.Instance
-			for _, i := range s.instances {
-				if i.ResourceID == *event.LogStreamName {
-					instance = &i
+
+			for i := range s.instances {
+				if s.instances[i].ResourceID == *event.LogStreamName {
+					instance = &s.instances[i]
 					break
 				}
 			}
@@ -89,6 +90,12 @@ func (s *scraper) scrape(ctx context.Context) (map[string][]prometheus.Metric, m
 				l.Errorf("Failed to find instance.")
 				continue
 			}
+
+			if *event.Timestamp <= instance.LastEventTimestamp {
+				continue
+			}
+
+			instance.LastEventTimestamp = *event.Timestamp
 			l = l.With("region", instance.Region).With("instance", instance.Instance)
 
 			// l.Debugf("Message:\n%s", *event.Message)
diff --git a/sessions/sessions.go b/sessions/sessions.go
index d93ccf4d..2f849070 100644
--- a/sessions/sessions.go
+++ b/sessions/sessions.go
@@ -23,6 +23,7 @@ type Instance struct {
 	ResourceID                 string
 	Labels                     map[string]string
 	EnhancedMonitoringInterval time.Duration
+	LastEventTimestamp         int64
 }
 
 func (i Instance) String() string {