diff --git a/weed/cluster/cluster.go b/weed/cluster/cluster.go
index 445b89a36..8496a7f6e 100644
--- a/weed/cluster/cluster.go
+++ b/weed/cluster/cluster.go
@@ -15,24 +15,13 @@ const (
 	BrokerType       = "broker"
 )
 
-type FilerGroup string
-type Filers struct {
-	members map[pb.ServerAddress]*ClusterNode
-	leaders *Leaders
-}
+type FilerGroupName string
+type DataCenter string
+type Rack string
+
 type Leaders struct {
 	leaders [3]pb.ServerAddress
 }
-
-type DataCenter string
-type Rack string
-type DataCenterBrokers struct {
-	brokers map[Rack]*RackBrokers
-}
-type RackBrokers struct {
-	brokers map[pb.ServerAddress]*ClusterNode
-}
-
 type ClusterNode struct {
 	Address    pb.ServerAddress
 	Version    string
@@ -41,92 +30,131 @@ type ClusterNode struct {
 	DataCenter DataCenter
 	Rack       Rack
 }
-
+type GroupMembers struct {
+	members map[pb.ServerAddress]*ClusterNode
+	leaders *Leaders
+}
+type ClusterNodeGroups struct {
+	groupMembers map[FilerGroupName]*GroupMembers
+	sync.RWMutex
+}
 type Cluster struct {
-	filerGroup2filers map[FilerGroup]*Filers
-	filersLock        sync.RWMutex
-	brokers           map[DataCenter]*DataCenterBrokers
-	brokersLock       sync.RWMutex
+	filerGroups  *ClusterNodeGroups
+	brokerGroups *ClusterNodeGroups
 }
 
-func NewCluster() *Cluster {
-	return &Cluster{
-		filerGroup2filers: make(map[FilerGroup]*Filers),
-		brokers:           make(map[DataCenter]*DataCenterBrokers),
+func newClusterNodeGroups() *ClusterNodeGroups {
+	return &ClusterNodeGroups{
+		groupMembers: map[FilerGroupName]*GroupMembers{},
 	}
 }
-
-func (cluster *Cluster) getFilers(filerGroup FilerGroup, createIfNotFound bool) *Filers {
-	filers, found := cluster.filerGroup2filers[filerGroup]
+func (g *ClusterNodeGroups) getGroupMembers(filerGroup FilerGroupName, createIfNotFound bool) *GroupMembers {
+	filers, found := g.groupMembers[filerGroup]
 	if !found && createIfNotFound {
-		filers = &Filers{
+		filers = &GroupMembers{
 			members: make(map[pb.ServerAddress]*ClusterNode),
 			leaders: &Leaders{},
 		}
-		cluster.filerGroup2filers[filerGroup] = filers
+		g.groupMembers[filerGroup] = filers
 	}
 	return filers
 }
 
-func (cluster *Cluster) AddClusterNode(ns, nodeType string, dataCenter DataCenter, rack Rack, address pb.ServerAddress, version string) []*master_pb.KeepConnectedResponse {
-	filerGroup := FilerGroup(ns)
+func (m *GroupMembers) addMember(dataCenter DataCenter, rack Rack, address pb.ServerAddress, version string) *ClusterNode {
+	if existingNode, found := m.members[address]; found {
+		existingNode.counter++
+		return nil
+	}
+	t := &ClusterNode{
+		Address:    address,
+		Version:    version,
+		counter:    1,
+		CreatedTs:  time.Now(),
+		DataCenter: dataCenter,
+		Rack:       rack,
+	}
+	m.members[address] = t
+	return t
+}
+func (m *GroupMembers) removeMember(address pb.ServerAddress) bool {
+	if existingNode, found := m.members[address]; !found {
+		return false
+	} else {
+		existingNode.counter--
+		if existingNode.counter <= 0 {
+			delete(m.members, address)
+			return true
+		}
+	}
+	return false
+}
+
+func (g *ClusterNodeGroups) AddClusterNode(filerGroup FilerGroupName, nodeType string, dataCenter DataCenter, rack Rack, address pb.ServerAddress, version string) []*master_pb.KeepConnectedResponse {
+	g.Lock()
+	defer g.Unlock()
+	m := g.getGroupMembers(filerGroup, true)
+	if t := m.addMember(dataCenter, rack, address, version); t != nil {
+		return ensureGroupLeaders(m, true, filerGroup, nodeType, address)
+	}
+	return nil
+}
+func (g *ClusterNodeGroups) RemoveClusterNode(filerGroup FilerGroupName, nodeType string, address pb.ServerAddress) []*master_pb.KeepConnectedResponse {
+	g.Lock()
+	defer g.Unlock()
+	m := g.getGroupMembers(filerGroup, false)
+	if m == nil {
+		return nil
+	}
+	if m.removeMember(address) {
+		return ensureGroupLeaders(m, false, filerGroup, nodeType, address)
+	}
+	return nil
+}
+func (g *ClusterNodeGroups) ListClusterNode(filerGroup FilerGroupName) (nodes []*ClusterNode) {
+	g.Lock()
+	defer g.Unlock()
+	m := g.getGroupMembers(filerGroup, false)
+	if m == nil {
+		return nil
+	}
+	for _, node := range m.members {
+		nodes = append(nodes, node)
+	}
+	return
+}
+func (g *ClusterNodeGroups) IsOneLeader(filerGroup FilerGroupName, address pb.ServerAddress) bool {
+	g.Lock()
+	defer g.Unlock()
+	m := g.getGroupMembers(filerGroup, false)
+	if m == nil {
+		return false
+	}
+	return m.leaders.isOneLeader(address)
+}
+func NewCluster() *Cluster {
+	return &Cluster{
+		filerGroups:  newClusterNodeGroups(),
+		brokerGroups: newClusterNodeGroups(),
+	}
+}
+
+func (cluster *Cluster) getGroupMembers(filerGroup FilerGroupName, nodeType string, createIfNotFound bool) *GroupMembers {
 	switch nodeType {
 	case FilerType:
-		cluster.filersLock.Lock()
-		defer cluster.filersLock.Unlock()
-		filers := cluster.getFilers(filerGroup, true)
-		if existingNode, found := filers.members[address]; found {
-			existingNode.counter++
-			return nil
-		}
-		filers.members[address] = &ClusterNode{
-			Address:    address,
-			Version:    version,
-			counter:    1,
-			CreatedTs:  time.Now(),
-			DataCenter: dataCenter,
-			Rack:       rack,
-		}
-		return ensureFilerLeaders(filers, true, filerGroup, nodeType, address)
+		return cluster.filerGroups.getGroupMembers(filerGroup, createIfNotFound)
 	case BrokerType:
-		cluster.brokersLock.Lock()
-		defer cluster.brokersLock.Unlock()
-		existingDataCenterBrokers, foundDataCenter := cluster.brokers[dataCenter]
-		if !foundDataCenter {
-			existingDataCenterBrokers = &DataCenterBrokers{
-				brokers: make(map[Rack]*RackBrokers),
-			}
-			cluster.brokers[dataCenter] = existingDataCenterBrokers
-		}
-		existingRackBrokers, foundRack := existingDataCenterBrokers.brokers[rack]
-		if !foundRack {
-			existingRackBrokers = &RackBrokers{
-				brokers: make(map[pb.ServerAddress]*ClusterNode),
-			}
-			existingDataCenterBrokers.brokers[rack] = existingRackBrokers
-		}
+		return cluster.brokerGroups.getGroupMembers(filerGroup, createIfNotFound)
+	}
+	return nil
+}
 
-		if existingBroker, found := existingRackBrokers.brokers[address]; found {
-			existingBroker.counter++
-			return nil
-		}
-		existingRackBrokers.brokers[address] = &ClusterNode{
-			Address:    address,
-			Version:    version,
-			counter:    1,
-			CreatedTs:  time.Now(),
-			DataCenter: dataCenter,
-			Rack:       rack,
-		}
-		return []*master_pb.KeepConnectedResponse{
-			{
-				ClusterNodeUpdate: &master_pb.ClusterNodeUpdate{
-					NodeType: nodeType,
-					Address:  string(address),
-					IsAdd:    true,
-				},
-			},
-		}
+func (cluster *Cluster) AddClusterNode(ns, nodeType string, dataCenter DataCenter, rack Rack, address pb.ServerAddress, version string) []*master_pb.KeepConnectedResponse {
+	filerGroup := FilerGroupName(ns)
+	switch nodeType {
+	case FilerType:
+		return cluster.filerGroups.AddClusterNode(filerGroup, nodeType, dataCenter, rack, address, version)
+	case BrokerType:
+		return cluster.brokerGroups.AddClusterNode(filerGroup, nodeType, dataCenter, rack, address, version)
 	case MasterType:
 		return []*master_pb.KeepConnectedResponse{
 			{
@@ -141,57 +169,13 @@ func (cluster *Cluster) AddClusterNode(ns, nodeType string, dataCenter DataCente
 	return nil
 }
 
-func (cluster *Cluster) RemoveClusterNode(ns string, nodeType string, dataCenter DataCenter, rack Rack, address pb.ServerAddress) []*master_pb.KeepConnectedResponse {
-	filerGroup := FilerGroup(ns)
+func (cluster *Cluster) RemoveClusterNode(ns string, nodeType string, address pb.ServerAddress) []*master_pb.KeepConnectedResponse {
+	filerGroup := FilerGroupName(ns)
 	switch nodeType {
 	case FilerType:
-		cluster.filersLock.Lock()
-		defer cluster.filersLock.Unlock()
-		filers := cluster.getFilers(filerGroup, false)
-		if filers == nil {
-			return nil
-		}
-		if existingNode, found := filers.members[address]; !found {
-			return nil
-		} else {
-			existingNode.counter--
-			if existingNode.counter <= 0 {
-				delete(filers.members, address)
-				return ensureFilerLeaders(filers, false, filerGroup, nodeType, address)
-			}
-		}
+		return cluster.filerGroups.RemoveClusterNode(filerGroup, nodeType, address)
 	case BrokerType:
-		cluster.brokersLock.Lock()
-		defer cluster.brokersLock.Unlock()
-
-		existingDataCenterBrokers, foundDataCenter := cluster.brokers[dataCenter]
-		if !foundDataCenter {
-			return nil
-		}
-		existingRackBrokers, foundRack := existingDataCenterBrokers.brokers[Rack(rack)]
-		if !foundRack {
-			return nil
-		}
-
-		existingBroker, found := existingRackBrokers.brokers[address]
-		if !found {
-			return nil
-		}
-		existingBroker.counter--
-		if existingBroker.counter <= 0 {
-			delete(existingRackBrokers.brokers, address)
-			return []*master_pb.KeepConnectedResponse{
-				{
-					ClusterNodeUpdate: &master_pb.ClusterNodeUpdate{
-						NodeType: nodeType,
-						Address:  string(address),
-						IsAdd:    false,
-					},
-				},
-			}
-		}
-		return nil
-
+		return cluster.brokerGroups.RemoveClusterNode(filerGroup, nodeType, address)
 	case MasterType:
 		return []*master_pb.KeepConnectedResponse{
 			{
@@ -206,44 +190,31 @@ func (cluster *Cluster) RemoveClusterNode(ns string, nodeType string, dataCenter
 	return nil
 }
 
-func (cluster *Cluster) ListClusterNode(filerGroup FilerGroup, nodeType string) (nodes []*ClusterNode) {
+func (cluster *Cluster) ListClusterNode(filerGroup FilerGroupName, nodeType string) (nodes []*ClusterNode) {
 	switch nodeType {
 	case FilerType:
-		cluster.filersLock.RLock()
-		defer cluster.filersLock.RUnlock()
-		filers := cluster.getFilers(filerGroup, false)
-		if filers == nil {
-			return
-		}
-		for _, node := range filers.members {
-			nodes = append(nodes, node)
-		}
+		return cluster.filerGroups.ListClusterNode(filerGroup)
 	case BrokerType:
-		cluster.brokersLock.RLock()
-		defer cluster.brokersLock.RUnlock()
-		for _, dcNodes := range cluster.brokers {
-			for _, rackNodes := range dcNodes.brokers {
-				for _, node := range rackNodes.brokers {
-					nodes = append(nodes, node)
-				}
-			}
-		}
+		return cluster.brokerGroups.ListClusterNode(filerGroup)
 	case MasterType:
 	}
 	return
 }
 
-func (cluster *Cluster) IsOneLeader(filerGroup FilerGroup, address pb.ServerAddress) bool {
-	filers := cluster.getFilers(filerGroup, false)
-	if filers == nil {
-		return false
+func (cluster *Cluster) IsOneLeader(filerGroup FilerGroupName, nodeType string, address pb.ServerAddress) bool {
+	switch nodeType {
+	case FilerType:
+		return cluster.filerGroups.IsOneLeader(filerGroup, address)
+	case BrokerType:
+		return cluster.brokerGroups.IsOneLeader(filerGroup, address)
+	case MasterType:
 	}
-	return filers.leaders.isOneLeader(address)
+	return false
 }
 
-func ensureFilerLeaders(filers *Filers, isAdd bool, filerGroup FilerGroup, nodeType string, address pb.ServerAddress) (result []*master_pb.KeepConnectedResponse) {
+func ensureGroupLeaders(m *GroupMembers, isAdd bool, filerGroup FilerGroupName, nodeType string, address pb.ServerAddress) (result []*master_pb.KeepConnectedResponse) {
 	if isAdd {
-		if filers.leaders.addLeaderIfVacant(address) {
+		if m.leaders.addLeaderIfVacant(address) {
 			// has added the address as one leader
 			result = append(result, &master_pb.KeepConnectedResponse{
 				ClusterNodeUpdate: &master_pb.ClusterNodeUpdate{
@@ -266,7 +237,7 @@ func ensureFilerLeaders(filers *Filers, isAdd bool, filerGroup FilerGroup, nodeT
 			})
 		}
 	} else {
-		if filers.leaders.removeLeaderIfExists(address) {
+		if m.leaders.removeLeaderIfExists(address) {
 
 			result = append(result, &master_pb.KeepConnectedResponse{
 				ClusterNodeUpdate: &master_pb.ClusterNodeUpdate{
@@ -282,8 +253,8 @@ func ensureFilerLeaders(filers *Filers, isAdd bool, filerGroup FilerGroup, nodeT
 			var shortestDuration int64 = math.MaxInt64
 			now := time.Now()
 			var candidateAddress pb.ServerAddress
-			for _, node := range filers.members {
-				if filers.leaders.isOneLeader(node.Address) {
+			for _, node := range m.members {
+				if m.leaders.isOneLeader(node.Address) {
 					continue
 				}
 				duration := now.Sub(node.CreatedTs).Nanoseconds()
@@ -293,7 +264,7 @@ func ensureFilerLeaders(filers *Filers, isAdd bool, filerGroup FilerGroup, nodeT
 				}
 			}
 			if candidateAddress != "" {
-				filers.leaders.addLeaderIfVacant(candidateAddress)
+				m.leaders.addLeaderIfVacant(candidateAddress)
 				// added a new leader
 				result = append(result, &master_pb.KeepConnectedResponse{
 					ClusterNodeUpdate: &master_pb.ClusterNodeUpdate{
diff --git a/weed/cluster/cluster_test.go b/weed/cluster/cluster_test.go
index 76cff2a3e..57ee4a023 100644
--- a/weed/cluster/cluster_test.go
+++ b/weed/cluster/cluster_test.go
@@ -16,7 +16,7 @@ func TestClusterAddRemoveNodes(t *testing.T) {
 	assert.Equal(t, []pb.ServerAddress{
 		pb.ServerAddress("111:1"),
 		pb.ServerAddress("111:2"),
-	}, c.getFilers("", false).leaders.GetLeaders())
+	}, c.getGroupMembers("", "filer", true).leaders.GetLeaders())
 
 	c.AddClusterNode("", "filer", "", "", pb.ServerAddress("111:3"), "23.45")
 	c.AddClusterNode("", "filer", "", "", pb.ServerAddress("111:4"), "23.45")
@@ -24,27 +24,27 @@ func TestClusterAddRemoveNodes(t *testing.T) {
 		pb.ServerAddress("111:1"),
 		pb.ServerAddress("111:2"),
 		pb.ServerAddress("111:3"),
-	}, c.getFilers("", false).leaders.GetLeaders())
+	}, c.getGroupMembers("", "filer", true).leaders.GetLeaders())
 
 	c.AddClusterNode("", "filer", "", "", pb.ServerAddress("111:5"), "23.45")
 	c.AddClusterNode("", "filer", "", "", pb.ServerAddress("111:6"), "23.45")
-	c.RemoveClusterNode("", "filer", "", "", pb.ServerAddress("111:4"))
+	c.RemoveClusterNode("", "filer", pb.ServerAddress("111:4"))
 	assert.Equal(t, []pb.ServerAddress{
 		pb.ServerAddress("111:1"),
 		pb.ServerAddress("111:2"),
 		pb.ServerAddress("111:3"),
-	}, c.getFilers("", false).leaders.GetLeaders())
+	}, c.getGroupMembers("", "filer", true).leaders.GetLeaders())
 
 	// remove oldest
-	c.RemoveClusterNode("", "filer", "", "", pb.ServerAddress("111:1"))
+	c.RemoveClusterNode("", "filer", pb.ServerAddress("111:1"))
 	assert.Equal(t, []pb.ServerAddress{
 		pb.ServerAddress("111:6"),
 		pb.ServerAddress("111:2"),
 		pb.ServerAddress("111:3"),
-	}, c.getFilers("", false).leaders.GetLeaders())
+	}, c.getGroupMembers("", "filer", true).leaders.GetLeaders())
 
 	// remove oldest
-	c.RemoveClusterNode("", "filer", "", "", pb.ServerAddress("111:1"))
+	c.RemoveClusterNode("", "filer", pb.ServerAddress("111:1"))
 
 }
 
@@ -66,7 +66,7 @@ func TestConcurrentAddRemoveNodes(t *testing.T) {
 		go func(i int) {
 			defer wg.Done()
 			address := strconv.Itoa(i)
-			node := c.RemoveClusterNode("", "filer", "", "", pb.ServerAddress(address))
+			node := c.RemoveClusterNode("", "filer", pb.ServerAddress(address))
 
 			if len(node) == 0 {
 				t.Errorf("TestConcurrentAddRemoveNodes: node[%s] not found", address)
diff --git a/weed/server/master_grpc_server.go b/weed/server/master_grpc_server.go
index d530e238e..363aa2979 100644
--- a/weed/server/master_grpc_server.go
+++ b/weed/server/master_grpc_server.go
@@ -259,7 +259,7 @@ func (ms *MasterServer) KeepConnected(stream master_pb.Seaweed_KeepConnectedServ
 	}
 
 	defer func() {
-		for _, update := range ms.Cluster.RemoveClusterNode(req.FilerGroup, req.ClientType, cluster.DataCenter(req.DataCenter), cluster.Rack(req.Rack), peerAddress) {
+		for _, update := range ms.Cluster.RemoveClusterNode(req.FilerGroup, req.ClientType, peerAddress) {
 			ms.broadcastToClients(update)
 		}
 		ms.deleteClient(clientName)
diff --git a/weed/server/master_grpc_server_cluster.go b/weed/server/master_grpc_server_cluster.go
index 31d7a6658..e368cb763 100644
--- a/weed/server/master_grpc_server_cluster.go
+++ b/weed/server/master_grpc_server_cluster.go
@@ -10,14 +10,14 @@ import (
 
 func (ms *MasterServer) ListClusterNodes(ctx context.Context, req *master_pb.ListClusterNodesRequest) (*master_pb.ListClusterNodesResponse, error) {
 	resp := &master_pb.ListClusterNodesResponse{}
-	filerGroup := cluster.FilerGroup(req.FilerGroup)
+	filerGroup := cluster.FilerGroupName(req.FilerGroup)
 	clusterNodes := ms.Cluster.ListClusterNode(filerGroup, req.ClientType)
 
 	for _, node := range clusterNodes {
 		resp.ClusterNodes = append(resp.ClusterNodes, &master_pb.ListClusterNodesResponse_ClusterNode{
 			Address:     string(node.Address),
 			Version:     node.Version,
-			IsLeader:    ms.Cluster.IsOneLeader(filerGroup, node.Address),
+			IsLeader:    ms.Cluster.IsOneLeader(filerGroup, req.ClientType, node.Address),
 			CreatedAtNs: node.CreatedTs.UnixNano(),
 			DataCenter:  string(node.DataCenter),
 			Rack:        string(node.Rack),
@@ -26,13 +26,13 @@ func (ms *MasterServer) ListClusterNodes(ctx context.Context, req *master_pb.Lis
 	return resp, nil
 }
 
-func (ms *MasterServer) GetOneFiler(filerGroup cluster.FilerGroup) pb.ServerAddress {
+func (ms *MasterServer) GetOneFiler(filerGroup cluster.FilerGroupName) pb.ServerAddress {
 
 	clusterNodes := ms.Cluster.ListClusterNode(filerGroup, cluster.FilerType)
 
 	var filers []pb.ServerAddress
 	for _, node := range clusterNodes {
-		if ms.Cluster.IsOneLeader(filerGroup, node.Address) {
+		if ms.Cluster.IsOneLeader(filerGroup, cluster.FilerType, node.Address) {
 			filers = append(filers, node.Address)
 		}
 	}
diff --git a/weed/server/master_server.go b/weed/server/master_server.go
index 756d14dbc..92d38d648 100644
--- a/weed/server/master_server.go
+++ b/weed/server/master_server.go
@@ -287,7 +287,7 @@ func (ms *MasterServer) startAdminScripts() {
 		for {
 			time.Sleep(time.Duration(sleepMinutes) * time.Minute)
 			if ms.Topo.IsLeader() {
-				shellOptions.FilerAddress = ms.GetOneFiler(cluster.FilerGroup(*shellOptions.FilerGroup))
+				shellOptions.FilerAddress = ms.GetOneFiler(cluster.FilerGroupName(*shellOptions.FilerGroup))
 				if shellOptions.FilerAddress == "" {
 					continue
 				}