doc: correct option name

Signed-off-by: Patrick Donnelly <[email protected]>

Author: batrick

doc/cephfs/troubleshooting.rst

@@ -98,7 +98,7 @@ things to do:
 
 .. code:: bash
 
-   ceph config set mds mds_heartbeat_reset_grace 3600
+   ceph config set mds mds_heartbeat_grace 3600
 
   This has the effect of having the MDS continue to send beacons to the monitors
   even when its internal "heartbeat" mechanism has not been reset (beat) in one