diff --git a/weed/server/master_grpc_server.go b/weed/server/master_grpc_server.go
index d2c86598e..93dce59d8 100644
--- a/weed/server/master_grpc_server.go
+++ b/weed/server/master_grpc_server.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net"
 	"strings"
+	"time"
 
 	"github.com/chrislusf/raft"
 	"github.com/chrislusf/seaweedfs/weed/glog"
@@ -172,6 +173,7 @@ func (ms *MasterServer) KeepConnected(stream master_pb.Seaweed_KeepConnectedServ
 		}
 	}()
 
+	ticker := time.NewTicker(5 * time.Second)
 	for {
 		select {
 		case message := <-messageChan:
@@ -179,6 +181,10 @@ func (ms *MasterServer) KeepConnected(stream master_pb.Seaweed_KeepConnectedServ
 				glog.V(0).Infof("=> client %v: %+v", clientName, message)
 				return err
 			}
+		case <-ticker.C:
+			if !ms.Topo.IsLeader() {
+				return raft.NotLeaderError
+			}
 		case <-stopChan:
 			return nil
 		}
diff --git a/weed/server/master_grpc_server_volume.go b/weed/server/master_grpc_server_volume.go
index 3a70fed5d..ae0819d2d 100644
--- a/weed/server/master_grpc_server_volume.go
+++ b/weed/server/master_grpc_server_volume.go
@@ -4,12 +4,18 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/chrislusf/raft"
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
 	"github.com/chrislusf/seaweedfs/weed/storage"
 	"github.com/chrislusf/seaweedfs/weed/topology"
 )
 
 func (ms *MasterServer) LookupVolume(ctx context.Context, req *master_pb.LookupVolumeRequest) (*master_pb.LookupVolumeResponse, error) {
+
+	if !ms.Topo.IsLeader() {
+		return nil, raft.NotLeaderError
+	}
+
 	resp := &master_pb.LookupVolumeResponse{}
 	volumeLocations := ms.lookupVolumeId(req.VolumeIds, req.Collection)
 
@@ -33,6 +39,10 @@ func (ms *MasterServer) LookupVolume(ctx context.Context, req *master_pb.LookupV
 
 func (ms *MasterServer) Assign(ctx context.Context, req *master_pb.AssignRequest) (*master_pb.AssignResponse, error) {
 
+	if !ms.Topo.IsLeader() {
+		return nil, raft.NotLeaderError
+	}
+
 	if req.Count == 0 {
 		req.Count = 1
 	}
@@ -87,6 +97,10 @@ func (ms *MasterServer) Assign(ctx context.Context, req *master_pb.AssignRequest
 
 func (ms *MasterServer) Statistics(ctx context.Context, req *master_pb.StatisticsRequest) (*master_pb.StatisticsResponse, error) {
 
+	if !ms.Topo.IsLeader() {
+		return nil, raft.NotLeaderError
+	}
+
 	if req.Replication == "" {
 		req.Replication = ms.defaultReplicaPlacement
 	}