diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index 21c3a3528..dc2dc5b53 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -903,8 +903,6 @@ func (s *Storage) mustLoadHourMetricIDs(hour uint64, name string) *hourMetricIDs
 	}
 
 	// Unmarshal header
-	isFull := encoding.UnmarshalUint64(src)
-	src = src[8:]
 	hourLoaded := encoding.UnmarshalUint64(src)
 	src = src[8:]
 	if hourLoaded != hour {
@@ -923,7 +921,6 @@ func (s *Storage) mustLoadHourMetricIDs(hour uint64, name string) *hourMetricIDs
 		return hm
 	}
 	hm.m = m
-	hm.isFull = isFull != 0
 	logger.Infof("loaded %s from %q in %.3f seconds; entriesCount: %d; sizeBytes: %d", name, path, time.Since(startTime).Seconds(), m.Len(), srcOrigLen)
 	return hm
 }
@@ -952,13 +949,8 @@ func (s *Storage) mustSaveHourMetricIDs(hm *hourMetricIDs, name string) {
 	logger.Infof("saving %s to %q...", name, path)
 	startTime := time.Now()
 	dst := make([]byte, 0, hm.m.Len()*8+24)
-	isFull := uint64(0)
-	if hm.isFull {
-		isFull = 1
-	}
 
 	// Marshal header
-	dst = encoding.MarshalUint64(dst, isFull)
 	dst = encoding.MarshalUint64(dst, hm.hour)
 
 	// Marshal hm.m
@@ -2347,18 +2339,15 @@ func (s *Storage) updateCurrHourMetricIDs(hour uint64) {
 
 	// Slow path: hm.m must be updated with non-empty s.pendingHourEntries.
 	var m *uint64set.Set
-	isFull := hm.isFull
 	if hm.hour == hour {
 		m = hm.m.Clone()
 	} else {
 		m = &uint64set.Set{}
-		isFull = true
 	}
 	m.Union(newMetricIDs.At(hour))
 	hmNew := &hourMetricIDs{
-		m:      m,
-		hour:   hour,
-		isFull: isFull,
+		m:    m,
+		hour: hour,
 	}
 	s.currHourMetricIDs.Store(hmNew)
 	if hm.hour != hour {
@@ -2372,9 +2361,8 @@ func (s *Storage) updateCurrHourMetricIDs(hour uint64) {
 }
 
 type hourMetricIDs struct {
-	m      *uint64set.Set
-	hour   uint64
-	isFull bool
+	m    *uint64set.Set
+	hour uint64
 }
 
 type generationTSID struct {
diff --git a/lib/storage/storage_test.go b/lib/storage/storage_test.go
index 03d48a362..6dc94a4a0 100644
--- a/lib/storage/storage_test.go
+++ b/lib/storage/storage_test.go
@@ -171,9 +171,6 @@ func TestUpdateCurrHourMetricIDs(t *testing.T) {
 		if hmCurr.m.Len() != 0 {
 			t.Fatalf("unexpected length of hm.m; got %d; want %d", hmCurr.m.Len(), 0)
 		}
-		if !hmCurr.isFull {
-			t.Fatalf("unexpected hmCurr.isFull; got %v; want %v", hmCurr.isFull, true)
-		}
 
 		hmPrev := s.prevHourMetricIDs.Load().(*hourMetricIDs)
 		if !reflect.DeepEqual(hmPrev, hmOrig) {
@@ -202,9 +199,6 @@ func TestUpdateCurrHourMetricIDs(t *testing.T) {
 		if !reflect.DeepEqual(hmCurr, hmOrig) {
 			t.Fatalf("unexpected hmCurr; got %v; want %v", hmCurr, hmOrig)
 		}
-		if hmCurr.isFull {
-			t.Fatalf("unexpected hmCurr.isFull; got %v; want %v", hmCurr.isFull, false)
-		}
 
 		hmPrev := s.prevHourMetricIDs.Load().(*hourMetricIDs)
 		hmEmpty := &hourMetricIDs{}
@@ -241,9 +235,6 @@ func TestUpdateCurrHourMetricIDs(t *testing.T) {
 		if !hmCurr.m.Equal(pendingHourEntries) {
 			t.Fatalf("unexpected hmCurr.m; got %v; want %v", hmCurr.m, pendingHourEntries)
 		}
-		if !hmCurr.isFull {
-			t.Fatalf("unexpected hmCurr.isFull; got %v; want %v", hmCurr.isFull, true)
-		}
 
 		hmPrev := s.prevHourMetricIDs.Load().(*hourMetricIDs)
 		if !reflect.DeepEqual(hmPrev, hmOrig) {
@@ -287,9 +278,6 @@ func TestUpdateCurrHourMetricIDs(t *testing.T) {
 		if !hmCurr.m.Equal(m) {
 			t.Fatalf("unexpected hm.m; got %v; want %v", hmCurr.m, m)
 		}
-		if hmCurr.isFull {
-			t.Fatalf("unexpected hmCurr.isFull; got %v; want %v", hmCurr.isFull, false)
-		}
 
 		hmPrev := s.prevHourMetricIDs.Load().(*hourMetricIDs)
 		hmEmpty := &hourMetricIDs{}