diff --git a/weed/topology/data_node.go b/weed/topology/data_node.go
index de428d38f..3103dc207 100644
--- a/weed/topology/data_node.go
+++ b/weed/topology/data_node.go
@@ -83,8 +83,7 @@ func (dn *DataNode) UpdateVolumes(actualVolumes []storage.VolumeInfo) (newVolume
 			disk.DeleteVolumeById(vid)
 			deletedVolumes = append(deletedVolumes, v)
 
-			deltaDiskUsages := newDiskUsages()
-			deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(v.DiskType))
+			deltaDiskUsage := &DiskUsageCounts{}
 			deltaDiskUsage.volumeCount = -1
 			if v.IsRemote() {
 				deltaDiskUsage.remoteVolumeCount = -1
@@ -92,7 +91,7 @@ func (dn *DataNode) UpdateVolumes(actualVolumes []storage.VolumeInfo) (newVolume
 			if !v.ReadOnly {
 				deltaDiskUsage.activeVolumeCount = -1
 			}
-			disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+			disk.UpAdjustDiskUsageDelta(types.ToDiskType(v.DiskType), deltaDiskUsage)
 		}
 	}
 	for _, v := range actualVolumes {
@@ -120,8 +119,7 @@ func (dn *DataNode) DeltaUpdateVolumes(newVolumes, deletedVolumes []storage.Volu
 		}
 		disk.DeleteVolumeById(v.Id)
 
-		deltaDiskUsages := newDiskUsages()
-		deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(v.DiskType))
+		deltaDiskUsage := &DiskUsageCounts{}
 		deltaDiskUsage.volumeCount = -1
 		if v.IsRemote() {
 			deltaDiskUsage.remoteVolumeCount = -1
@@ -129,7 +127,7 @@ func (dn *DataNode) DeltaUpdateVolumes(newVolumes, deletedVolumes []storage.Volu
 		if !v.ReadOnly {
 			deltaDiskUsage.activeVolumeCount = -1
 		}
-		disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		disk.UpAdjustDiskUsageDelta(types.ToDiskType(v.DiskType), deltaDiskUsage)
 	}
 	for _, v := range newVolumes {
 		dn.doAddOrUpdateVolume(v)
@@ -143,7 +141,6 @@ func (dn *DataNode) AdjustMaxVolumeCounts(maxVolumeCounts map[string]uint32) {
 			// the volume server may have set the max to zero
 			continue
 		}
-		deltaDiskUsages := newDiskUsages()
 		dt := types.ToDiskType(diskType)
 		currentDiskUsage := dn.diskUsages.getOrCreateDisk(dt)
 		currentDiskUsageMaxVolumeCount := atomic.LoadInt64(&currentDiskUsage.maxVolumeCount)
@@ -151,9 +148,9 @@ func (dn *DataNode) AdjustMaxVolumeCounts(maxVolumeCounts map[string]uint32) {
 			continue
 		}
 		disk := dn.getOrCreateDisk(dt.String())
-		deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(dt)
-		deltaDiskUsage.maxVolumeCount = int64(maxVolumeCount) - currentDiskUsageMaxVolumeCount
-		disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		disk.UpAdjustDiskUsageDelta(dt, &DiskUsageCounts{
+			maxVolumeCount: int64(maxVolumeCount) - currentDiskUsageMaxVolumeCount,
+		})
 	}
 }
 
diff --git a/weed/topology/data_node_ec.go b/weed/topology/data_node_ec.go
index 100b44f59..839499982 100644
--- a/weed/topology/data_node_ec.go
+++ b/weed/topology/data_node_ec.go
@@ -26,12 +26,10 @@ func (dn *DataNode) UpdateEcShards(actualShards []*erasure_coding.EcVolumeInfo)
 	existingEcShards := dn.GetEcShards()
 
 	// find out the newShards and deletedShards
-	var newShardCount, deletedShardCount int
 	for _, ecShards := range existingEcShards {
 
+		var newShardCount, deletedShardCount int
 		disk := dn.getOrCreateDisk(ecShards.DiskType)
-		deltaDiskUsages := newDiskUsages()
-		deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(ecShards.DiskType))
 
 		vid := ecShards.VolumeId
 		if actualEcShards, ok := actualEcShardMap[vid]; !ok {
@@ -52,8 +50,11 @@ func (dn *DataNode) UpdateEcShards(actualShards []*erasure_coding.EcVolumeInfo)
 			}
 		}
 
-		deltaDiskUsage.ecShardCount = int64(newShardCount - deletedShardCount)
-		disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		if (newShardCount - deletedShardCount) != 0 {
+			disk.UpAdjustDiskUsageDelta(types.ToDiskType(ecShards.DiskType), &DiskUsageCounts{
+				ecShardCount: int64(newShardCount - deletedShardCount),
+			})
+		}
 
 	}
 
@@ -65,10 +66,9 @@ func (dn *DataNode) UpdateEcShards(actualShards []*erasure_coding.EcVolumeInfo)
 		newShards = append(newShards, ecShards)
 
 		disk := dn.getOrCreateDisk(ecShards.DiskType)
-		deltaDiskUsages := newDiskUsages()
-		deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(ecShards.DiskType))
-		deltaDiskUsage.ecShardCount = int64(ecShards.ShardIdCount())
-		disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		disk.UpAdjustDiskUsageDelta(types.ToDiskType(ecShards.DiskType), &DiskUsageCounts{
+			ecShardCount: int64(ecShards.ShardIdCount()),
+		})
 	}
 
 	if len(newShards) > 0 || len(deletedShards) > 0 {
diff --git a/weed/topology/disk.go b/weed/topology/disk.go
index 4597bfc29..6d789e34b 100644
--- a/weed/topology/disk.go
+++ b/weed/topology/disk.go
@@ -152,8 +152,7 @@ func (d *Disk) AddOrUpdateVolume(v storage.VolumeInfo) (isNew, isChanged bool) {
 }
 
 func (d *Disk) doAddOrUpdateVolume(v storage.VolumeInfo) (isNew, isChanged bool) {
-	deltaDiskUsages := newDiskUsages()
-	deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(v.DiskType))
+	deltaDiskUsage := &DiskUsageCounts{}
 	if oldV, ok := d.volumes[v.Id]; !ok {
 		d.volumes[v.Id] = v
 		deltaDiskUsage.volumeCount = 1
@@ -164,7 +163,7 @@ func (d *Disk) doAddOrUpdateVolume(v storage.VolumeInfo) (isNew, isChanged bool)
 			deltaDiskUsage.activeVolumeCount = 1
 		}
 		d.UpAdjustMaxVolumeId(v.Id)
-		d.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		d.UpAdjustDiskUsageDelta(types.ToDiskType(v.DiskType), deltaDiskUsage)
 		isNew = true
 	} else {
 		if oldV.IsRemote() != v.IsRemote() {
@@ -174,7 +173,7 @@ func (d *Disk) doAddOrUpdateVolume(v storage.VolumeInfo) (isNew, isChanged bool)
 			if oldV.IsRemote() {
 				deltaDiskUsage.remoteVolumeCount = -1
 			}
-			d.UpAdjustDiskUsageDelta(deltaDiskUsages)
+			d.UpAdjustDiskUsageDelta(types.ToDiskType(v.DiskType), deltaDiskUsage)
 		}
 		isChanged = d.volumes[v.Id].ReadOnly != v.ReadOnly
 		d.volumes[v.Id] = v
diff --git a/weed/topology/disk_ec.go b/weed/topology/disk_ec.go
index 4f950025f..1fea29272 100644
--- a/weed/topology/disk_ec.go
+++ b/weed/topology/disk_ec.go
@@ -29,10 +29,12 @@ func (d *Disk) AddOrUpdateEcShard(s *erasure_coding.EcVolumeInfo) {
 		delta = existing.ShardBits.ShardIdCount() - oldCount
 	}
 
-	deltaDiskUsages := newDiskUsages()
-	deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(string(d.Id())))
-	deltaDiskUsage.ecShardCount = int64(delta)
-	d.UpAdjustDiskUsageDelta(deltaDiskUsages)
+	if delta == 0 {
+		return
+	}
+	d.UpAdjustDiskUsageDelta(types.ToDiskType(string(d.Id())), &DiskUsageCounts{
+		ecShardCount: int64(delta),
+	})
 
 }
 
@@ -45,10 +47,11 @@ func (d *Disk) DeleteEcShard(s *erasure_coding.EcVolumeInfo) {
 		existing.ShardBits = existing.ShardBits.Minus(s.ShardBits)
 		delta := existing.ShardBits.ShardIdCount() - oldCount
 
-		deltaDiskUsages := newDiskUsages()
-		deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(string(d.Id())))
-		deltaDiskUsage.ecShardCount = int64(delta)
-		d.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		if delta != 0 {
+			d.UpAdjustDiskUsageDelta(types.ToDiskType(string(d.Id())), &DiskUsageCounts{
+				ecShardCount: int64(delta),
+			})
+		}
 
 		if existing.ShardBits.ShardIdCount() == 0 {
 			delete(d.ecShards, s.VolumeId)
diff --git a/weed/topology/node.go b/weed/topology/node.go
index d33bbce2b..aa178b561 100644
--- a/weed/topology/node.go
+++ b/weed/topology/node.go
@@ -21,7 +21,7 @@ type Node interface {
 	String() string
 	AvailableSpaceFor(option *VolumeGrowOption) int64
 	ReserveOneVolume(r int64, option *VolumeGrowOption) (*DataNode, error)
-	UpAdjustDiskUsageDelta(deltaDiskUsages *DiskUsages)
+	UpAdjustDiskUsageDelta(diskType types.DiskType, diskUsage *DiskUsageCounts)
 	UpAdjustMaxVolumeId(vid needle.VolumeId)
 	GetDiskUsages() *DiskUsages
 
@@ -214,13 +214,11 @@ func (n *NodeImpl) ReserveOneVolume(r int64, option *VolumeGrowOption) (assigned
 	return nil, errors.New("No free volume slot found!")
 }
 
-func (n *NodeImpl) UpAdjustDiskUsageDelta(deltaDiskUsages *DiskUsages) { //can be negative
-	for diskType, diskUsage := range deltaDiskUsages.usages {
-		existingDisk := n.getOrCreateDisk(diskType)
-		existingDisk.addDiskUsageCounts(diskUsage)
-	}
+func (n *NodeImpl) UpAdjustDiskUsageDelta(diskType types.DiskType, diskUsage *DiskUsageCounts) { //can be negative
+	existingDisk := n.getOrCreateDisk(diskType)
+	existingDisk.addDiskUsageCounts(diskUsage)
 	if n.parent != nil {
-		n.parent.UpAdjustDiskUsageDelta(deltaDiskUsages)
+		n.parent.UpAdjustDiskUsageDelta(diskType, diskUsage)
 	}
 }
 func (n *NodeImpl) UpAdjustMaxVolumeId(vid needle.VolumeId) { //can be negative
@@ -244,7 +242,9 @@ func (n *NodeImpl) LinkChildNode(node Node) {
 func (n *NodeImpl) doLinkChildNode(node Node) {
 	if n.children[node.Id()] == nil {
 		n.children[node.Id()] = node
-		n.UpAdjustDiskUsageDelta(node.GetDiskUsages())
+		for dt, du := range node.GetDiskUsages().usages {
+			n.UpAdjustDiskUsageDelta(dt, du)
+		}
 		n.UpAdjustMaxVolumeId(node.GetMaxVolumeId())
 		node.SetParent(n)
 		glog.V(0).Infoln(n, "adds child", node.Id())
@@ -258,7 +258,9 @@ func (n *NodeImpl) UnlinkChildNode(nodeId NodeId) {
 	if node != nil {
 		node.SetParent(nil)
 		delete(n.children, node.Id())
-		n.UpAdjustDiskUsageDelta(node.GetDiskUsages().negative())
+		for dt, du := range node.GetDiskUsages().negative().usages {
+			n.UpAdjustDiskUsageDelta(dt, du)
+		}
 		glog.V(0).Infoln(n, "removes", node.Id())
 	}
 }
diff --git a/weed/topology/topology_event_handling.go b/weed/topology/topology_event_handling.go
index ff1c642a6..109f29ee0 100644
--- a/weed/topology/topology_event_handling.go
+++ b/weed/topology/topology_event_handling.go
@@ -65,10 +65,9 @@ func (t *Topology) SetVolumeCapacityFull(volumeInfo storage.VolumeInfo) bool {
 		if !volumeInfo.ReadOnly {
 
 			disk := dn.getOrCreateDisk(volumeInfo.DiskType)
-			deltaDiskUsages := newDiskUsages()
-			deltaDiskUsage := deltaDiskUsages.getOrCreateDisk(types.ToDiskType(volumeInfo.DiskType))
-			deltaDiskUsage.activeVolumeCount = -1
-			disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+			disk.UpAdjustDiskUsageDelta(types.ToDiskType(volumeInfo.DiskType), &DiskUsageCounts{
+				activeVolumeCount: -1,
+			})
 
 		}
 	}
@@ -96,7 +95,9 @@ func (t *Topology) UnRegisterDataNode(dn *DataNode) {
 	}
 
 	negativeUsages := dn.GetDiskUsages().negative()
-	dn.UpAdjustDiskUsageDelta(negativeUsages)
+	for dt, du := range negativeUsages.usages {
+		dn.UpAdjustDiskUsageDelta(dt, du)
+	}
 	dn.DeltaUpdateVolumes([]storage.VolumeInfo{}, dn.GetVolumes())
 	dn.DeltaUpdateEcShards([]*erasure_coding.EcVolumeInfo{}, dn.GetEcShards())
 	if dn.Parent() != nil {
diff --git a/weed/topology/volume_growth_test.go b/weed/topology/volume_growth_test.go
index 1624ec32a..49dd0957c 100644
--- a/weed/topology/volume_growth_test.go
+++ b/weed/topology/volume_growth_test.go
@@ -122,10 +122,9 @@ func setup(topologyLayout string) *Topology {
 				}
 
 				disk := server.getOrCreateDisk("")
-				deltaDiskUsages := newDiskUsages()
-				deltaDiskUsage := deltaDiskUsages.getOrCreateDisk("")
-				deltaDiskUsage.maxVolumeCount = int64(serverMap["limit"].(float64))
-				disk.UpAdjustDiskUsageDelta(deltaDiskUsages)
+				disk.UpAdjustDiskUsageDelta("", &DiskUsageCounts{
+					maxVolumeCount: int64(serverMap["limit"].(float64)),
+				})
 
 			}
 		}