diff --git a/weed/messaging/broker/broker_grpc_server_publish.go b/weed/messaging/broker/broker_grpc_server_publish.go
index 61e53b433..573706c06 100644
--- a/weed/messaging/broker/broker_grpc_server_publish.go
+++ b/weed/messaging/broker/broker_grpc_server_publish.go
@@ -1,11 +1,15 @@
 package broker
 
 import (
+	"crypto/md5"
+	"fmt"
 	"io"
 
 	"github.com/golang/protobuf/proto"
 
+	"github.com/chrislusf/seaweedfs/weed/filer2"
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
 	"github.com/chrislusf/seaweedfs/weed/pb/messaging_pb"
 )
 
@@ -44,9 +48,19 @@ func (broker *MessageBroker) Publish(stream messaging_pb.SeaweedMessaging_Publis
 		Topic:     in.Init.Topic,
 		Partition: in.Init.Partition,
 	}
+
+	tpDir := fmt.Sprintf("%s/%s/%s", filer2.TopicsDir, tp.Namespace, tp.Topic)
+	md5File := fmt.Sprintf("p%02d.md5", tp.Partition)
+	// println("chan data stored under", tpDir, "as", md5File)
+
+	if exists, err := filer_pb.Exists(broker, tpDir, md5File, false); err == nil && exists {
+		return fmt.Errorf("channel is already closed")
+	}
+
 	tl := broker.topicLocks.RequestLock(tp, topicConfig, true)
 	defer broker.topicLocks.ReleaseLock(tp, true)
 
+	md5hash := md5.New()
 	// process each message
 	for {
 		// println("recv")
@@ -78,8 +92,16 @@ func (broker *MessageBroker) Publish(stream messaging_pb.SeaweedMessaging_Publis
 			break
 		}
 
+		md5hash.Write(in.Data.Value)
+
+	}
+
+	if err := broker.appendToFile(tpDir+"/"+md5File, topicConfig, md5hash.Sum(nil)); err != nil {
+		glog.V(0).Infof("err writing %s: %v", md5File, err)
 	}
 
+	// fmt.Printf("received md5 %X\n", md5hash.Sum(nil))
+
 	// send the close ack
 	// println("server send ack closing")
 	if err := stream.Send(&messaging_pb.PublishResponse{IsClosed: true}); err != nil {
diff --git a/weed/messaging/broker/broker_grpc_server_subscribe.go b/weed/messaging/broker/broker_grpc_server_subscribe.go
index f8fd16a14..86ee6923d 100644
--- a/weed/messaging/broker/broker_grpc_server_subscribe.go
+++ b/weed/messaging/broker/broker_grpc_server_subscribe.go
@@ -57,6 +57,7 @@ func (broker *MessageBroker) Subscribe(stream messaging_pb.SeaweedMessaging_Subs
 		lastReadTime = time.Unix(0, in.Init.TimestampNs)
 	case messaging_pb.SubscriberMessage_InitMessage_LATEST:
 	case messaging_pb.SubscriberMessage_InitMessage_EARLIEST:
+		lastReadTime = time.Unix(0, 0)
 	}
 	var processedTsNs int64
 
diff --git a/weed/messaging/broker/topic_lock.go b/weed/messaging/broker/topic_lock.go
index f3a66a2f5..4c4803275 100644
--- a/weed/messaging/broker/topic_lock.go
+++ b/weed/messaging/broker/topic_lock.go
@@ -17,7 +17,7 @@ type TopicPartition struct {
 	Partition int32
 }
 const (
-	TopicPartitionFmt = "%s/%s_%2d"
+	TopicPartitionFmt = "%s/%s_%02d"
 )
 func (tp *TopicPartition) String() string {
 	return fmt.Sprintf(TopicPartitionFmt, tp.Namespace, tp.Topic, tp.Partition)
@@ -106,6 +106,7 @@ func (tl *TopicLocks) ReleaseLock(partition TopicPartition, isPublisher bool) {
 	}
 	if lock.subscriberCount <= 0 && lock.publisherCount <= 0 {
 		delete(tl.locks, partition)
+		lock.logBuffer.Shutdown()
 	}
 }
 
diff --git a/weed/messaging/msgclient/sub_chan.go b/weed/messaging/msgclient/sub_chan.go
index aae5c0c71..ed25a850c 100644
--- a/weed/messaging/msgclient/sub_chan.go
+++ b/weed/messaging/msgclient/sub_chan.go
@@ -55,8 +55,8 @@ func (mc *MessagingClient) NewSubChannel(chanName string) (*SubChannel, error) {
 				close(t.ch)
 				return
 			}
-			t.md5hash.Write(resp.Data.Value)
 			t.ch <- resp.Data.Value
+			t.md5hash.Write(resp.Data.Value)
 		}
 	}()
 
diff --git a/weed/util/log_buffer/log_buffer.go b/weed/util/log_buffer/log_buffer.go
index 6ba7f3737..67c44dc57 100644
--- a/weed/util/log_buffer/log_buffer.go
+++ b/weed/util/log_buffer/log_buffer.go
@@ -98,13 +98,14 @@ func (m *LogBuffer) AddToBuffer(partitionKey, data []byte) {
 }
 
 func (m *LogBuffer) Shutdown() {
+	m.Lock()
+	defer m.Unlock()
+
 	if m.isStopping {
 		return
 	}
 	m.isStopping = true
-	m.Lock()
 	toFlush := m.copyToFlush()
-	m.Unlock()
 	m.flushChan <- toFlush
 	close(m.flushChan)
 }
@@ -123,10 +124,14 @@ func (m *LogBuffer) loopInterval() {
 	for !m.isStopping {
 		time.Sleep(m.flushInterval)
 		m.Lock()
+		if m.isStopping {
+			m.Unlock()
+			return
+		}
 		// println("loop interval")
 		toFlush := m.copyToFlush()
-		m.Unlock()
 		m.flushChan <- toFlush
+		m.Unlock()
 	}
 }