doc/cephfs: update about changing max_mds FS setting variable

Update the documentation for CephFs admininstration as well
troubleshooting.

Signed-off-by: Rishabh Dave <[email protected]>

Author: rishabh-d-dave

doc/cephfs/administration.rst

@@ -61,10 +61,17 @@ is a subset of the same information from the ``ceph fs dump`` command.
 
 ::
 
-    ceph fs set <file system name> <var> <val>
+    ceph fs set <file system name> <var> <val> [--yes-i-really-mean-it]
 
 Change a setting on a file system. These settings are specific to the named
-file system and do not affect other file systems.
+file system and do not affect other file systems. Confirmation flag is only
+needed for changing ``max_mds`` when cluster is unhealthy.
+
+.. note:: It is mandatory to pass confirmation flag (--yes--i-really-mean-it)
+   for modifying FS setting variable ``max_mds`` when cluster is unhealthy.
+   It has been added a precaution to tell users that modifying ``max_mds``
+   during troubleshooting or recovery might not help. Instead, it might
+   further destabilize the cluster.
 
 ::
 

doc/cephfs/troubleshooting.rst

@@ -128,6 +128,11 @@ things to do:
 
   That prevents any clients from establishing new sessions with the MDS.
 
+* **Dont tweak max_mds** Modifying the FS setting variable ``max_mds`` is
+  sometimes perceived as a good step during troubleshooting or recovery effort.
+  Instead, doing so might further destabilize the cluster. If ``max_mds`` must
+  be changed in such circumstances, run the command to change ``max_mds`` with
+  the confirmation flag (``--yes-i-really-mean-it``)
 
 
 Expediting MDS journal trim