Updates by comments

Author: AArdeev

doc/admin/troubleshoot.rst

@@ -256,7 +256,7 @@ This issue can be fixed in two ways:
 
 ..  NOTE::
 
-    To avoid brain split between two masters, one of the instances may be put in the :ref:`isolated mode <_configuration_reference_isolated_mode>`.
+    If one of the instances must be isolated during troubleshooting, it can be put to the :ref:`isolated mode <_configuration_reference_isolated_mode>`.
 
 Then, restart replication as described in :ref:`Restarting replication <replication-master-master-resolve-conflict>`.
 

doc/code_snippets/snippets/config/instances.enabled/isolated_mode/config.yaml

@@ -7,4 +7,4 @@ groups:
           i-002: {}
           i-003: {}
           i-004:
-            isolated: true
+            isolated: true

doc/reference/configuration/configuration_reference.rst

@@ -2848,15 +2848,14 @@ The option takes boolean values, by default it is set to ``false``.
 
 The isolated mode allows the user to temporarily isolate an instance and perform maintenance activities on it. 
 
-The isolated mode moves the instance to the read-only state, in which:
+In the isolated mode:
 
+*   The instance is moved to the read-only state
 *   iproto stops listening for new connections
 *   iproto drops all the current connections
 *   The instance is disconnected from all the replication upstreams
 *   Other replicaset members exclude the isolated instance from the replication upstreams
 
-Once the mode is enabled, any request trying to change persistent data will fail with the ``ER_READONLY`` error.
-
 ..  NOTE::
 
     Isolated instance can't be bootstrapped (a local snapshot is required to start).