diff --git a/.gitignore b/.gitignore
index 42e539f..8959171 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,5 +3,5 @@ build
 .DS_Store
 nohup.out
 build_config.mk
-var
+var*
 _workspace
\ No newline at end of file
diff --git a/cmd/ledis-server/main.go b/cmd/ledis-server/main.go
index e132506..32be6c2 100644
--- a/cmd/ledis-server/main.go
+++ b/cmd/ledis-server/main.go
@@ -15,12 +15,15 @@ import (
 )
 
 var configFile = flag.String("config", "", "ledisdb config file")
+var addr = flag.String("addr", "", "ledisdb listen address")
+var dataDir = flag.String("data_dir", "", "ledisdb base data dir")
 var dbName = flag.String("db_name", "", "select a db to use, it will overwrite the config's db name")
 var usePprof = flag.Bool("pprof", false, "enable pprof")
 var pprofPort = flag.Int("pprof_port", 6060, "pprof http port")
 var slaveof = flag.String("slaveof", "", "make the server a slave of another instance")
 var readonly = flag.Bool("readonly", false, "set readonly mode, salve server is always readonly")
 var rpl = flag.Bool("rpl", false, "enable replication or not, slave server is always enabled")
+var rplSync = flag.Bool("rpl_sync", false, "enable sync replication or not")
 
 func main() {
 	runtime.GOMAXPROCS(runtime.NumCPU())
@@ -42,6 +45,14 @@ func main() {
 		return
 	}
 
+	if len(*addr) > 0 {
+		cfg.Addr = *addr
+	}
+
+	if len(*dataDir) > 0 {
+		cfg.DataDir = *dataDir
+	}
+
 	if len(*dbName) > 0 {
 		cfg.DBName = *dbName
 	}
@@ -53,6 +64,7 @@ func main() {
 	} else {
 		cfg.Readonly = *readonly
 		cfg.UseReplication = *rpl
+		cfg.Replication.Sync = *rplSync
 	}
 
 	var app *server.App
diff --git a/server/cmd_replication.go b/server/cmd_replication.go
index aefd1ac..b401f35 100644
--- a/server/cmd_replication.go
+++ b/server/cmd_replication.go
@@ -1,6 +1,7 @@
 package server
 
 import (
+	"encoding/binary"
 	"fmt"
 	"github.com/siddontang/go/hack"
 	"github.com/siddontang/go/num"
@@ -94,6 +95,8 @@ func fullsyncCommand(c *client) error {
 	return nil
 }
 
+var dummyBuf = make([]byte, 8)
+
 func syncCommand(c *client) error {
 	args := c.args
 	if len(args) != 1 {
@@ -122,11 +125,20 @@ func syncCommand(c *client) error {
 
 	c.syncBuf.Reset()
 
+	c.syncBuf.Write(dummyBuf)
+
 	if _, _, err := c.app.ldb.ReadLogsToTimeout(logId, &c.syncBuf, 30); err != nil {
 		return err
 	} else {
 		buf := c.syncBuf.Bytes()
 
+		stat, err = c.app.ldb.ReplicationStat()
+		if err != nil {
+			return err
+		}
+
+		binary.BigEndian.PutUint64(buf, stat.LastID)
+
 		c.resp.writeBulk(buf)
 	}
 
diff --git a/server/info.go b/server/info.go
index 7ccb587..ccdba98 100644
--- a/server/info.go
+++ b/server/info.go
@@ -3,6 +3,7 @@ package server
 import (
 	"bytes"
 	"fmt"
+	"github.com/siddontang/go/sync2"
 	"os"
 	"runtime"
 	"strings"
@@ -25,8 +26,11 @@ type info struct {
 	}
 
 	Replication struct {
-		PubLogNum       int64
-		PubLogTotalTime int64 //milliseconds
+		PubLogNum          sync2.AtomicInt64
+		PubLogAckNum       sync2.AtomicInt64
+		PubLogTotalAckTime sync2.AtomicDuration
+
+		MasterLastLogID sync2.AtomicUint64
 	}
 }
 
@@ -156,13 +160,15 @@ func (i *info) dumpReplication(buf *bytes.Buffer) {
 	}
 	i.app.slock.Unlock()
 
-	num := i.Replication.PubLogNum
+	num := i.Replication.PubLogNum.Get()
 	p = append(p, infoPair{"pub_log_num", num})
 
-	if num != 0 {
-		p = append(p, infoPair{"pub_log_per_time", i.Replication.PubLogTotalTime / num})
+	ackNum := i.Replication.PubLogAckNum.Get()
+	totalTime := i.Replication.PubLogTotalAckTime.Get().Nanoseconds() / 1e6
+	if ackNum != 0 {
+		p = append(p, infoPair{"pub_log_ack_per_time", totalTime / ackNum})
 	} else {
-		p = append(p, infoPair{"pub_log_per_time", 0})
+		p = append(p, infoPair{"pub_log_ack_per_time", 0})
 	}
 
 	p = append(p, infoPair{"slaveof", i.app.cfg.SlaveOf})
@@ -181,6 +187,8 @@ func (i *info) dumpReplication(buf *bytes.Buffer) {
 		p = append(p, infoPair{"commit_log_id", 0})
 	}
 
+	p = append(p, infoPair{"master_last_log_id", i.Replication.MasterLastLogID.Get()})
+
 	i.dumpPairs(buf, p...)
 }
 
diff --git a/server/replication.go b/server/replication.go
index 25e4a8d..47230b1 100644
--- a/server/replication.go
+++ b/server/replication.go
@@ -16,7 +16,6 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"sync/atomic"
 	"time"
 )
 
@@ -263,6 +262,17 @@ func (m *master) sync() error {
 
 	buf := m.syncBuf.Bytes()
 
+	if len(buf) < 8 {
+		return fmt.Errorf("inavlid sync size %d", len(buf))
+	}
+
+	m.app.info.Replication.MasterLastLogID.Set(num.BytesToUint64(buf))
+
+	var t bytes.Buffer
+	m.app.info.dumpReplication(&t)
+
+	buf = buf[8:]
+
 	if len(buf) == 0 {
 		return nil
 	}
@@ -370,6 +380,8 @@ func (app *App) publishNewLog(l *rpl.Log) {
 		return
 	}
 
+	app.info.Replication.PubLogNum.Add(1)
+
 	app.slock.Lock()
 
 	total := (len(app.slaves) + 1) / 2
@@ -414,6 +426,6 @@ func (app *App) publishNewLog(l *rpl.Log) {
 	}
 
 	stopTime := time.Now()
-	atomic.AddInt64(&app.info.Replication.PubLogNum, 1)
-	atomic.AddInt64(&app.info.Replication.PubLogTotalTime, stopTime.Sub(startTime).Nanoseconds()/1e6)
+	app.info.Replication.PubLogAckNum.Add(1)
+	app.info.Replication.PubLogTotalAckTime.Add(stopTime.Sub(startTime))
 }