diff --git a/etc/emqx.conf b/etc/emqx.conf
index 1d623953b..8ec796746 100644
--- a/etc/emqx.conf
+++ b/etc/emqx.conf
@@ -550,6 +550,14 @@ zone.external.acl_deny_action = ignore
 ## Numbers delimited by `|'. Zero or negative is to disable.
 zone.external.force_gc_policy = 1000|1MB
 
+## Max message queue length and total heap size to force shutdown
+## connection/session process.
+## Message queue here is the Erlang process mailbox, but not the number
+## of queued MQTT messages of QoS 1 and 2.
+##
+## Numbers delimited by `|'. Zero or negative is to disable.
+zone.external.force_shutdown_policy = 10000|1024MB
+
 ## Maximum MQTT packet size allowed.
 ##
 ## Value: Bytes
diff --git a/priv/emqx.schema b/priv/emqx.schema
index 5c7f421ce..937965275 100644
--- a/priv/emqx.schema
+++ b/priv/emqx.schema
@@ -400,7 +400,7 @@ end}.
   {datatype, {enum, [debug, info, notice, warning, error, critical, alert, emergency, all]}}
 ]}.
 
-{mapping, "log.primary_level", "emqx.primary_log_level", [
+{mapping, "log.primary_level", "kernel.primary_log_level", [
    {default, error},
    {datatype, {enum, [debug, info, notice, warning, error, critical, alert, emergency, all]}}
 ]}.
@@ -420,7 +420,7 @@ end}.
   {datatype, file}
 ]}.
 
-{mapping, "log.chars_limit", "log.chars_limit", [
+{mapping, "log.chars_limit", "kernel.logger", [
   {default, 1024},
   {datatype, integer}
 ]}.
@@ -462,10 +462,6 @@ end}.
   hidden
 ]}.
 
-{translation, "emqx.primary_log_level", fun(Conf) ->
-    cuttlefish:conf_get("log.level", Conf)
-end}.
-
 {translation, "kernel.logger", fun(Conf) ->
     LogTo = cuttlefish:conf_get("log.to", Conf),
     LogLevel = cuttlefish:conf_get("log.level", Conf),
diff --git a/src/emqx_app.erl b/src/emqx_app.erl
index 2ef660521..bc9d58408 100644
--- a/src/emqx_app.erl
+++ b/src/emqx_app.erl
@@ -31,7 +31,7 @@ start(_Type, _Args) ->
     %%   kernel config `logger_level` before starting the erlang vm.
     %% This is because the latter approach an annoying debug msg will be printed out:
     %%   "[debug] got_unexpected_message {'EXIT',<0.1198.0>,normal}"
-    logger:set_primary_config(level, application:get_env(emqx, primary_log_level, error)),
+    logger:set_primary_config(level, application:get_env(kernel, primary_log_level, error)),
 
     print_banner(),
     ekka:start(),