diff --git a/src/os/WBThrottle.h b/src/os/WBThrottle.h
index b7812326750..d1feb9bf848 100644
--- a/src/os/WBThrottle.h
+++ b/src/os/WBThrottle.h
@@ -134,6 +134,7 @@ public:
   WBThrottle(CephContext *cct);
   ~WBThrottle();
 
+  void start();
   void stop();
   /// Set fs as XFS or BTRFS
   void set_fs(FS new_fs) {