diff --git a/cluster.go b/cluster.go
index 31b69f5..0095613 100644
--- a/cluster.go
+++ b/cluster.go
@@ -174,8 +174,8 @@ func (d Driver) Open(name string) (driver.Conn, error) {
 }
 
 // NewDriver returns an initialized Cluster driver, using upstreamDriver as backend
-func NewDriver(upstreamDriver driver.Driver) Driver {
-	m := expvar.NewMap("ClusterSql")
+func NewDriver(id string, upstreamDriver driver.Driver) Driver {
+	m := expvar.NewMap(id)
 	Time := new(expvar.String)
 	Time.Set(time.Now().String())
 	m.Set("FirstInstanciated", Time)
diff --git a/cluster_test.go b/cluster_test.go
index 2e9bf1c..8c9c8db 100644
--- a/cluster_test.go
+++ b/cluster_test.go
@@ -65,7 +65,7 @@ func TestOpen(t *testing.T) {
 		}
 	}
 
-	d := NewDriver(mysql.MySQLDriver{})
+	d := NewDriver("ClusterSql", mysql.MySQLDriver{})
 
 	for _, ncfg := range cfg.Nodes {
 		if ncfg.Password != "" {