diff --git a/controller/cluster.go b/controller/cluster.go
index 2b975d2..eea8ff8 100644
--- a/controller/cluster.go
+++ b/controller/cluster.go
@@ -341,6 +341,10 @@ func (c *ClusterChecker) migrationLoop() {
 			return
 		case <-ticker.C:
 			c.clusterMu.Lock()
+			if c.cluster == nil {
+				c.clusterMu.Unlock()
+				continue
+			}
 			clonedCluster := c.cluster.Clone()
 			c.clusterMu.Unlock()
 			if clonedCluster == nil {
diff --git a/store/cluster.go b/store/cluster.go
index b345e23..d4713dd 100644
--- a/store/cluster.go
+++ b/store/cluster.go
@@ -78,10 +78,6 @@ func NewCluster(name string, nodes []string, replicas int) (*Cluster, error) {
 }
 
 func (cluster *Cluster) Clone() *Cluster {
-	if cluster == nil {
-		return nil
-	}
-
 	clone := &Cluster{
 		Name:   cluster.Name,
 		Shards: make([]*Shard, 0),
diff --git a/store/cluster_test.go b/store/cluster_test.go
index 889bf03..cb62545 100644
--- a/store/cluster_test.go
+++ b/store/cluster_test.go
@@ -30,10 +30,6 @@ import (
 )
 
 func TestCluster_Clone(t *testing.T) {
-	var cluster *Cluster
-	emptyCluster := cluster.Clone()
-	require.Nil(t, emptyCluster)
-
 	cluster, err := NewCluster("test", []string{"node1", "node2", "node3"}, 1)
 	require.NoError(t, err)