diff --git a/server/api/redirector.go b/server/api/redirector.go
index 3f570940d71..78a291aaade 100644
--- a/server/api/redirector.go
+++ b/server/api/redirector.go
@@ -80,9 +80,7 @@ func newCustomReverseProxies(urls []url.URL) *customReverseProxies {
 		client: &http.Client{},
 	}
 
-	for _, u := range urls {
-		p.urls = append(p.urls, u)
-	}
+	p.urls = append(p.urls, urls...)
 
 	return p
 }
diff --git a/server/util.go b/server/util.go
index b4ca1109aab..990c61f032b 100644
--- a/server/util.go
+++ b/server/util.go
@@ -207,15 +207,6 @@ func (t *slowLogTxn) Commit() (*clientv3.TxnResponse, error) {
 	return resp, errors.Trace(err)
 }
 
-func sliceClone(strs []string) []string {
-	data := make([]string, 0, len(strs))
-	for _, str := range strs {
-		data = append(data, str)
-	}
-
-	return data
-}
-
 // GetMembers return a slice of Members.
 func GetMembers(etcdClient *clientv3.Client) ([]*pdpb.Member, error) {
 	listResp, err := etcdutil.ListEtcdMembers(etcdClient)