diff --git a/weed/command/filer_sync.go b/weed/command/filer_sync.go
index dc7c569c3..b7da1baf9 100644
--- a/weed/command/filer_sync.go
+++ b/weed/command/filer_sync.go
@@ -12,6 +12,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/replication/sink/filersink"
 	"github.com/chrislusf/seaweedfs/weed/replication/source"
 	"github.com/chrislusf/seaweedfs/weed/security"
+	statsCollect "github.com/chrislusf/seaweedfs/weed/stats"
 	"github.com/chrislusf/seaweedfs/weed/util"
 	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"google.golang.org/grpc"
@@ -40,6 +41,7 @@ type SyncOptions struct {
 	bFromTsMs       *int64
 	aProxyByFiler   *bool
 	bProxyByFiler   *bool
+	metricsHttpPort *int
 	clientId        int32
 }
 
@@ -72,6 +74,7 @@ func init() {
 	syncOptions.bFromTsMs = cmdFilerSynchronize.Flag.Int64("b.fromTsMs", 0, "synchronization from timestamp on filer B. The unit is millisecond")
 	syncCpuProfile = cmdFilerSynchronize.Flag.String("cpuprofile", "", "cpu profile output file")
 	syncMemProfile = cmdFilerSynchronize.Flag.String("memprofile", "", "memory profile output file")
+	syncOptions.metricsHttpPort = cmdFilerSynchronize.Flag.Int("metricsPort", 0, "metrics listen port")
 	syncOptions.clientId = util.RandomInt32()
 }
 
@@ -103,6 +106,9 @@ func runFilerSynchronize(cmd *Command, args []string) bool {
 	filerA := pb.ServerAddress(*syncOptions.filerA)
 	filerB := pb.ServerAddress(*syncOptions.filerB)
 
+	// start filer.sync metrics server
+	go statsCollect.StartMetricsServer(*syncOptions.metricsHttpPort)
+
 	// read a filer signature
 	aFilerSignature, aFilerErr := replication.ReadFilerSignature(grpcDialOption, filerA)
 	if aFilerErr != nil {
@@ -210,14 +216,17 @@ func doSubscribeFilerMetaChanges(clientId int32, grpcDialOption grpc.DialOption,
 	}
 
 	var lastLogTsNs = time.Now().Nanosecond()
+	var clientName = fmt.Sprintf("syncFrom_%s_To_%s", string(sourceFiler), string(targetFiler))
 	processEventFnWithOffset := pb.AddOffsetFunc(processEventFn, 3*time.Second, func(counter int64, lastTsNs int64) error {
 		now := time.Now().Nanosecond()
 		glog.V(0).Infof("sync %s to %s progressed to %v %0.2f/sec", sourceFiler, targetFiler, time.Unix(0, lastTsNs), float64(counter)/(float64(now-lastLogTsNs)/1e9))
 		lastLogTsNs = now
+		// collect synchronous offset
+		statsCollect.FilerSyncOffsetGauge.WithLabelValues(sourceFiler.String(), targetFiler.String(), clientName, sourcePath).Set(float64(lastTsNs))
 		return setOffset(grpcDialOption, targetFiler, getSignaturePrefixByPath(sourcePath), sourceFilerSignature, lastTsNs)
 	})
 
-	return pb.FollowMetadata(sourceFiler, grpcDialOption, "syncTo_"+string(targetFiler), clientId,
+	return pb.FollowMetadata(sourceFiler, grpcDialOption, clientName, clientId,
 		sourcePath, nil, sourceFilerOffsetTsNs, 0, targetFilerSignature, processEventFnWithOffset, pb.RetryForeverOnError)
 
 }
diff --git a/weed/server/filer_grpc_server_sub_meta.go b/weed/server/filer_grpc_server_sub_meta.go
index 0540400a3..da710234b 100644
--- a/weed/server/filer_grpc_server_sub_meta.go
+++ b/weed/server/filer_grpc_server_sub_meta.go
@@ -2,6 +2,7 @@ package weed_server
 
 import (
 	"fmt"
+	"github.com/chrislusf/seaweedfs/weed/stats"
 	"strings"
 	"time"
 
@@ -229,6 +230,9 @@ func (fs *FilerServer) eachEventNotificationFn(req *filer_pb.SubscribeMetadataRe
 			}
 		}
 
+		// collect timestamps for path
+		stats.FilerServerLastSendTsOfSubscribeGauge.WithLabelValues(fs.option.Host.String(), req.ClientName, req.PathPrefix).Set(float64(tsNs))
+
 		message := &filer_pb.SubscribeMetadataResponse{
 			Directory:         dirPath,
 			EventNotification: eventNotification,
diff --git a/weed/stats/metrics.go b/weed/stats/metrics.go
index 943aafff9..207b37c81 100644
--- a/weed/stats/metrics.go
+++ b/weed/stats/metrics.go
@@ -77,6 +77,14 @@ var (
 			Buckets:   prometheus.ExponentialBuckets(0.0001, 2, 24),
 		}, []string{"type"})
 
+	FilerServerLastSendTsOfSubscribeGauge = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "SeaweedFS",
+			Subsystem: "filer",
+			Name:      "last_send_timestamp_of_subscribe",
+			Help:      "The last send timestamp of the filer subscription.",
+		}, []string{"sourceFiler", "clientName", "path"})
+
 	FilerStoreCounter = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
 			Namespace: "SeaweedFS",
@@ -94,6 +102,14 @@ var (
 			Buckets:   prometheus.ExponentialBuckets(0.0001, 2, 24),
 		}, []string{"store", "type"})
 
+	FilerSyncOffsetGauge = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "SeaweedFS",
+			Subsystem: "filerSync",
+			Name:      "sync_offset",
+			Help:      "The offset of the filer synchronization service.",
+		}, []string{"sourceFiler", "targetFiler", "clientName", "path"})
+
 	VolumeServerRequestCounter = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
 			Namespace: "SeaweedFS",
@@ -179,6 +195,8 @@ func init() {
 	Gather.MustRegister(FilerRequestHistogram)
 	Gather.MustRegister(FilerStoreCounter)
 	Gather.MustRegister(FilerStoreHistogram)
+	Gather.MustRegister(FilerSyncOffsetGauge)
+	Gather.MustRegister(FilerServerLastSendTsOfSubscribeGauge)
 	Gather.MustRegister(collectors.NewGoCollector())
 	Gather.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))