diff --git a/ocaml/xapi/xapi_host.ml b/ocaml/xapi/xapi_host.ml
index e2cece5cb5c..e31c96c7a81 100644
--- a/ocaml/xapi/xapi_host.ml
+++ b/ocaml/xapi/xapi_host.ml
@@ -2790,6 +2790,7 @@ let set_uefi_certificates ~__context ~host:_ ~value:_ =
 let set_iscsi_iqn ~__context ~host ~value =
   if value = "" then
     raise Api_errors.(Server_error (invalid_value, ["value"; value])) ;
+  D.debug "%s: iqn=%S" __FUNCTION__ value ;
   (* Note, the following sequence is carefully written - see the
      other-config watcher thread in xapi_host_helpers.ml *)
   Db.Host.remove_from_other_config ~__context ~self:host ~key:"iscsi_iqn" ;
diff --git a/ocaml/xapi/xapi_host_helpers.ml b/ocaml/xapi/xapi_host_helpers.ml
index 834b34beb4b..7b9ac9d7a2e 100644
--- a/ocaml/xapi/xapi_host_helpers.ml
+++ b/ocaml/xapi/xapi_host_helpers.ml
@@ -497,10 +497,13 @@ module Configuration = struct
     [iqn; hostname_chopped]
 
   let set_initiator_name iqn =
+    if iqn = "" then
+      raise Api_errors.(Server_error (invalid_value, ["iqn"; iqn])) ;
     let hostname = Unix.gethostname () in
     (* CA-377454 - robustness, create dir if necessary *)
     Unixext.mkdir_rec "/var/lock/sm/iscsiadm" 0o700 ;
     let args = make_set_initiator_args iqn hostname in
+    D.debug "%s: iqn=%S" __FUNCTION__ iqn ;
     ignore (Helpers.call_script !Xapi_globs.set_iSCSI_initiator_script args)
 
   let set_multipathing enabled =
@@ -541,6 +544,7 @@ module Configuration = struct
             | Some "" ->
                 ()
             | Some iqn when iqn <> host_rec.API.host_iscsi_iqn ->
+                D.debug "%s: iqn=%S" __FUNCTION__ iqn ;
                 Client.Client.Host.set_iscsi_iqn ~rpc ~session_id ~host:host_ref
                   ~value:iqn
             | _ ->