diff --git a/pkg/apis/pingcap/v1alpha1/backup.go b/pkg/apis/pingcap/v1alpha1/backup.go
index 6768366aee8..2992fced120 100644
--- a/pkg/apis/pingcap/v1alpha1/backup.go
+++ b/pkg/apis/pingcap/v1alpha1/backup.go
@@ -29,7 +29,7 @@ var (
 		RoutineConcurrency: 100,
 	}
 
-	// defaultCleanOption is default clean option
+	// defaultCleanOption is default clean option.
 	defaultCleanOption = CleanOption{
 		PageSize:          10000,
 		RetryCount:        5,