diff --git a/etc/ledis.json b/etc/ledis.json
index 92d9f93..dcf2ea5 100644
--- a/etc/ledis.json
+++ b/etc/ledis.json
@@ -1,8 +1,8 @@
 {
     "addr": "127.0.0.1:6380",
+    "data_dir": "/tmp/ledis_server",
     "db": {
         "data_db" : {
-            "path": "/tmp/ledisdb",
             "compression": false,
             "block_size": 32768,
             "write_buffer_size": 67108864,
diff --git a/ledis/ledis.go b/ledis/ledis.go
index 8ba83b2..ad2bc76 100644
--- a/ledis/ledis.go
+++ b/ledis/ledis.go
@@ -13,11 +13,13 @@ type Config struct {
 	DataDir string `json:"data_dir"`
 
 	//data_db path is data_dir/data
+	//if you not set leveldb path, use data_dir/data
 	DataDB leveldb.Config `json:"data_db"`
 
 	//binlog path is data_dir/binlog
 	//you muse set binlog name to enable binlog
-	BinLog replication.BinLogConfig `json:"binlog"`
+	//if you not set bin log path, use data_dir/bin_log
+	BinLog replication.BinLogConfig `json:"bin_log"`
 }
 
 type DB struct {
@@ -61,7 +63,10 @@ func OpenWithConfig(cfg *Config) (*Ledis, error) {
 		return nil, fmt.Errorf("must set correct data_dir")
 	}
 
-	cfg.DataDB.Path = path.Join(cfg.DataDir, "data")
+	if len(cfg.DataDB.Path) == 0 {
+		cfg.DataDB.Path = path.Join(cfg.DataDir, "data")
+	}
+
 	ldb, err := leveldb.OpenWithConfig(&cfg.DataDB)
 	if err != nil {
 		return nil, err
@@ -74,7 +79,9 @@ func OpenWithConfig(cfg *Config) (*Ledis, error) {
 	l.ldb = ldb
 
 	if len(cfg.BinLog.Name) > 0 {
-		cfg.BinLog.Path = path.Join(cfg.DataDir, "binlog")
+		if len(cfg.BinLog.Path) == 0 {
+			cfg.BinLog.Path = path.Join(cfg.DataDir, "bin_log")
+		}
 		l.binlog, err = replication.NewBinLogWithConfig(&cfg.BinLog)
 		if err != nil {
 			return nil, err
diff --git a/ledis/replication_test.go b/ledis/replication_test.go
index f22617e..a3a2d6f 100644
--- a/ledis/replication_test.go
+++ b/ledis/replication_test.go
@@ -17,7 +17,7 @@ func TestReplication(t *testing.T) {
 	master, err = Open([]byte(`
         {
             "data_dir" : "/tmp/test_repl/master",
-            "binlog": {
+            "bin_log": {
                 "name" : "ledis"
             }
         }
diff --git a/server/app.go b/server/app.go
index 9e7e029..5e414ee 100644
--- a/server/app.go
+++ b/server/app.go
@@ -1,6 +1,7 @@
 package server
 
 import (
+	"fmt"
 	"github.com/siddontang/ledisdb/ledis"
 	"net"
 	"strings"
@@ -17,6 +18,14 @@ type App struct {
 }
 
 func NewApp(cfg *Config) (*App, error) {
+	if len(cfg.DataDir) == 0 {
+		return nil, fmt.Errorf("must set data_dir first")
+	}
+
+	if len(cfg.DB.DataDir) == 0 {
+		cfg.DB.DataDir = cfg.DataDir
+	}
+
 	app := new(App)
 
 	app.closed = false
diff --git a/server/app_test.go b/server/app_test.go
index efaf08e..3357ddd 100644
--- a/server/app_test.go
+++ b/server/app_test.go
@@ -38,9 +38,9 @@ func startTestApp() {
 
 		var d = []byte(`
             {
+                "data_dir" : "/tmp/testdb",
                 "addr" : "127.0.0.1:16380",
                 "db" : {
-                    "data_dir" : "/tmp/testdb",
                     "data_db" : {
                         "compression":true,
                         "block_size" : 32768,
diff --git a/server/config.go b/server/config.go
index 5e98694..592b51d 100644
--- a/server/config.go
+++ b/server/config.go
@@ -3,13 +3,20 @@ package server
 import (
 	"encoding/json"
 	"github.com/siddontang/ledisdb/ledis"
+	"github.com/siddontang/ledisdb/replication"
 	"io/ioutil"
 )
 
 type Config struct {
 	Addr string `json:"addr"`
 
+	DataDir string `json:"data_dir"`
+
+	//if you not set db path, use data_dir
 	DB ledis.Config `json:"db"`
+
+	//if you not set relay log path, use data_dir/realy_log
+	RelayLog replication.RelayLogConfig `json:"relay_log"`
 }
 
 func NewConfig(data json.RawMessage) (*Config, error) {