diff --git a/etc/emqttd.conf b/etc/emqttd.conf
index 71c6d0a96..f71829c79 100644
--- a/etc/emqttd.conf
+++ b/etc/emqttd.conf
@@ -8,11 +8,11 @@
 ## Erlang VM
 ##--------------------------------------------------------------------
 
-## Erlang Node Name
+## Erlang node name
 vm.nodename = emqttd@127.0.0.1
 
 ## Cookie for distributed erlang
-vm.setcookie = emqttdsecretcookie
+vm.setcookie = emqsecretcookie
 
 ## SMP support: enable, auto, disable
 vm.smp = auto
@@ -39,14 +39,14 @@ vm.max_ets_tables = 256000
 ## Tweak GC to run more often
 vm.fullsweep_after = 1000
 
-vm.crash_dump = log/emqttd_crash.dump
+## Crash dump
+vm.crash_dump = log/crash.dump
 
 ##--------------------------------------------------------------------
 ## Log
 ##--------------------------------------------------------------------
 
 
-
 ##--------------------------------------------------------------------
 ## MQTT Protocol
 ##--------------------------------------------------------------------
@@ -65,39 +65,39 @@ mqtt.client_idle_timeout = 30
 ##--------------------------------------------------------------------
 
 ## TCP Listener: 1883, 127.0.0.1:1883, ::1:1883
-mqtt.listener.tcp = 1883
-mqtt.listener.tcp.acceptors = 16
-mqtt.listener.tcp.max_clients = 512
+## mqtt.listener.tcp = 1883
+## mqtt.listener.tcp.acceptors = 16
+## mqtt.listener.tcp.max_clients = 512
 ## Rate Limit. Format is 'burst,rate', Unit is KB/Sec
 ## mqtt.listener.tcp.rate_limit = 100,10
 ## Mount Point
 ## mqtt.listener.tcp.mount_point = prefix/
 ## TCP Socket Options. Set buffer if hight thoughtput
-mqtt.listener.tcp.opts.recbuf = 4096
-mqtt.listener.tcp.opts.sndbuf = 4096
-mqtt.listener.tcp.opts.buffer = 4096
-mqtt.listener.tcp.opts.nodelay = true
-mqtt.listener.tcp.opts.backlog = 1024
+## mqtt.listener.tcp.opts.recbuf = 4096
+## mqtt.listener.tcp.opts.sndbuf = 4096
+## mqtt.listener.tcp.opts.buffer = 4096
+## mqtt.listener.tcp.opts.nodelay = true
+## mqtt.listener.tcp.opts.backlog = 1024
 
 ## SSL Listener
-mqtt.listener.ssl = 883
-mqtt.listener.ssl.acceptors = 4
-mqtt.listener.ssl.max_clients = 512
+## mqtt.listener.ssl = 883
+## mqtt.listener.ssl.acceptors = 4
+## mqtt.listener.ssl.max_clients = 512
 ## Rate Limit. Format is 'burst,rate', Unit is KB/Sec
 ## mqtt.listener.ssl.rate_limit = 100,10
 ## Mount Point
 ## mqtt.listener.ssl.mount_point = prefix/
-mqtt.listener.ssl.opts.handshake_timeout = 10 ## Seconds
-mqtt.listener.ssl.opts.certfile = etc/ssl/cert.pem
-mqtt.listener.ssl.opts.keyfile = etc/ssl/key.pem
-mqtt.listener.ssl.opts.cacertfile = etc/ssl/cacert.pem
+## mqtt.listener.ssl.opts.handshake_timeout = 10 ## Seconds
+## mqtt.listener.ssl.opts.certfile = etc/ssl/cert.pem
+## mqtt.listener.ssl.opts.keyfile = etc/ssl/key.pem
+## mqtt.listener.ssl.opts.cacertfile = etc/ssl/cacert.pem
 ## mqtt.listener.ssl.opts.verify = verify_peer
 ## mqtt.listener.ssl.opts.failed_if_no_peer_cert = true
 
 ## HTTP Listener
-mqtt.listener.http = 8083
-mqtt.listener.http.acceptors = 4
-mqtt.listener.http.max_clients = 64
+## mqtt.listener.http = 8083
+## mqtt.listener.http.acceptors = 4
+## mqtt.listener.http.max_clients = 64
 
 ##--------------------------------------------------------------------
 ## MQTT Session
@@ -119,8 +119,13 @@ mqtt.session.max_awaiting_rel = 0
 ## Statistics Collection Interval(seconds)
 mqtt.session.collect_interval = 0
 
-## Expired after 2 day (unit: minute)
-mqtt.session.expired_after = 2880
+## Expired after 2 day:
+## w - week
+## d - day
+## h - hour
+## m - minute
+## s - second
+mqtt.session.expired_after = 2d
 
 ##--------------------------------------------------------------------
 ## MQTT Queue
@@ -137,10 +142,10 @@ mqtt.queue.type = simple
 mqtt.queue.max_length = infinity
 
 ## Low-water mark of queued messages
-mqtt.queue.low_watermark = 0.2
+mqtt.queue.low_watermark = 20%
 
 ## High-water mark of queued messages
-mqtt.queue.high_watermark = 0.6
+mqtt.queue.high_watermark = 60%
 
 ## Queue Qos0 messages?
 mqtt.queue.qos0 = true
@@ -175,40 +180,40 @@ mqtt.bridge.ping_down_interval = 1 ## Second
 ##-------------------------------------------------------------------
 
 ## Dir of plugins' config
-mqtt.plugins.etc_dir = etc/plugins/
+## mqtt.plugins.etc_dir = etc/plugins/
 
 ## File to store loaded plugin names.
-mqtt.plugins.loaded_file = data/loaded_plugins
+## mqtt.plugins.loaded_file = data/loaded_plugins
 
 ##-------------------------------------------------------------------
 ## MQTT Modules
 ##-------------------------------------------------------------------
 
 ## Enable retainer module
-mqtt.module.retainer = on
+## mqtt.module.retainer = on
 ## disc: disc_copies, ram: ram_copies
-mqtt.module.retainer.storage_type = disc
+## mqtt.module.retainer.storage_type = disc
 ## Max number of retained messages
-mqtt.module.retainer.max_message_num = 100000
+## mqtt.module.retainer.max_message_num = 100000
 ## Max Payload Size of retained message
-mqtt.module.retainer.max_playload_size = 65536
+## mqtt.module.retainer.max_playload_size = 65536
 ## Expired after seconds, never expired if 0
-mqtt.module.retainer.expired_after = 0
+## mqtt.module.retainer.expired_after = 0
 
 ## Enable presence module
 ## Client presence management module. Publish presence messages when
 ## client connected or disconnected.
-mqtt.module.presence = on
-mqtt.module.presence.qos = 0
+## mqtt.module.presence = on
+## mqtt.module.presence.qos = 0
 
 ## Enable subscription module
 ## Subscribe topics automatically when client connected
-mqtt.module.subscription = on
-mqtt.module.subscription.topics = $client/%c,1;topic2,1
+## mqtt.module.subscription = on
+## mqtt.module.subscription.topics = $client/%c,1;topic2,1
 
 ## [Rewrite](https://github.com/emqtt/emqttd/wiki/Rewrite)
-mqtt.module.rewrite = off
-mqtt.module.rewrite.config = etc/modules/rewrite.conf
+## mqtt.module.rewrite = off
+## mqtt.module.rewrite.config = etc/modules/rewrite.conf
 
 ##-------------------------------------------------------------------
 ## System Monitor
@@ -216,15 +221,13 @@ mqtt.module.rewrite.config = etc/modules/rewrite.conf
 
 ## Long GC, don't monitor in production mode for:
 ## https://github.com/erlang/otp/blob/feb45017da36be78d4c5784d758ede619fa7bfd3/erts/emulator/beam/erl_gc.c#L421
-
 sysmon.long_gc = false
 
 ## Long Schedule(ms)
 sysmon.long_schedule = 240
 
 ## 8M words. 32MB on 32-bit VM, 64MB on 64-bit VM.
-## 8 * 1024 * 1024
-sysmon.large_heap = 8388608
+sysmon.large_heap = 8MB
 
 ## Busy Port
 sysmon.busy_port = false
diff --git a/priv/emqttd.schema b/priv/emqttd.schema
index 2b5311462..2f56739a7 100644
--- a/priv/emqttd.schema
+++ b/priv/emqttd.schema
@@ -1,31 +1,35 @@
 %%-*- mode: erlang -*-
-%% EMQ 3.0 Config Mapping
+%% EMQ 3.0 config mapping
 
 %%--------------------------------------------------------------------
 %% Erlang VM Args
 %%--------------------------------------------------------------------
 
+%% @doc Erlang node name
 {mapping, "vm.nodename", "vm_args.-name", [
-  {default, "{{node}}"}
+  {default, "emqttd@127.0.0.1"}
 ]}.
 
+%% @doc Secret cookie for distributed erlang node
 {mapping, "vm.setcookie", "vm_args.-setcookie", [
-  {default, "emqttd"}
+  {default, "emqsecretcookie"}
 ]}.
 
+%% @doc SMP Support
 {mapping, "vm.smp", "vm_args.-smp", [
-  {default, enable},
+  {default, auto},
   {datatype, {enum, [enable, auto, disable]}},
   hidden
 ]}.
 
+%% @doc Enable Kernel Poll
 {mapping, "vm.kernel_poll", "vm_args.+K", [
   {default, on},
   {datatype, flag},
   hidden
 ]}.
 
-%% More information at: http://erlang.org/doc/man/erl.html
+%% @doc More information at: http://erlang.org/doc/man/erl.html
 {mapping, "vm.async_threads", "vm_args.+A", [
   {default, 64},
   {datatype, integer},
@@ -52,12 +56,7 @@
 {validator, "range4ports", "must be 1024 to 134217727",
  fun(X) -> X >= 1024 andalso X =< 134217727 end}.
 
-%% @doc For nodes with many busy_dist_port events, Basho recommends
-%% raising the sender-side network distribution buffer size.
-%% 32MB may not be sufficient for some workloads and is a suggested
-%% starting point. Erlangers may know this as +zdbbl.
-%% The Erlang/OTP default is 1024 (1 megabyte).
-%% See: http://www.erlang.org/doc/man/erl.html#%2bzdbbl
+%% @doc http://www.erlang.org/doc/man/erl.html#%2bzdbbl
 {mapping, "vm.dist_buffer_size", "vm_args.+zdbbl", [
   {datatype, bytesize},
   {commented, "32MB"},
@@ -83,14 +82,7 @@
  end
 }.
 
-%% @doc A non-negative integer which indicates how many times
-%% generational garbage collections can be done without forcing a
-%% fullsweep collection. In low-memory systems (especially without
-%% virtual memory), setting the value to 0 can help to conserve
-%% memory.
-%%
-%% More information at:
-%% http://www.erlang.org/doc/man/erlang.html#system_flag-2
+%% @doc http://www.erlang.org/doc/man/erlang.html#system_flag-2
 {mapping, "vm.fullsweep_after", "vm_args.-env ERL_FULLSWEEP_AFTER", [
   {default, 1000},
   {datatype, integer},
@@ -103,7 +95,7 @@
 
 %% Note: OTP R15 and earlier uses -env ERL_MAX_ETS_TABLES,
 %% R16+ uses +e
-%% @doc Raise the ETS table limit
+%% @doc The ETS table limit
 {mapping, "vm.max_ets_tables",
   cuttlefish:otp("R16", "vm_args.+e", "vm_args.-env ERL_MAX_ETS_TABLES"), [
   {default, 256000},
@@ -118,38 +110,232 @@
   hidden
 ]}.
 
-{mapping, "mqtt.max_clientid_len", "emqttd.mqtt_max_clientid_len", [
+%%--------------------------------------------------------------------
+%% MQTT Protocol
+%%--------------------------------------------------------------------
+
+%% @doc Set the Max ClientId Length Allowed.
+{mapping, "mqtt.max_clientid_len", "emqttd.mqtt_protocol", [
   {default, 1024},
   {datatype, integer}
 ]}.
 
-{mapping, "mqtt.max_packet_size", "emqttd.mqtt_max_packet_size", [
+%% @doc Max Packet Size Allowed, 64K by default.
+{mapping, "mqtt.max_packet_size", "emqttd.mqtt_protocol", [
+  {default, "64KB"},
   {datatype, bytesize}
 ]}.
 
-{mapping, "mqtt.client_idle_timeout", "emqttd.mqtt_client_idle_timeout", [
+%% @doc Client Idle Timeout.
+{mapping, "mqtt.client_idle_timeout", "emqttd.mqtt_protocol", [
+  {default, 30},
   {datatype, integer}
 ]}.
 
+{translation, "emqttd.mqtt_protocol", fun(Conf) ->
+  [{max_clientid_len,    cuttlefish:conf_get("mqtt.max_clientid_len", Conf)},
+   {max_packet_size,     cuttlefish:conf_get("mqtt.max_packet_size", Conf)},
+   {client_idle_timeout, cuttlefish:conf_get("mqtt.client_idle_timeout", Conf)}]
+end}.
+
+%%--------------------------------------------------------------------
+%% MQTT Session
+%%--------------------------------------------------------------------
+
+%% @doc Max number of QoS 1 and 2 messages that can be “inflight” at one time.
+%% 0 means no limit
+{mapping, "mqtt.session.max_inflight", "emqttd.mqtt_session", [
+  {default, 100},
+  {datatype, integer}
+]}.
+
+
+%% @doc Retry interval for redelivering QoS1/2 messages.
+{mapping, "mqtt.session.unack_retry_interval", "emqttd.mqtt_session", [
+  {default, 60},
+  {datatype, integer}
+]}.
+
+%% @doc Awaiting PUBREL Timeout
+{mapping, "mqtt.session.await_rel_timeout", "emqttd.mqtt_session", [
+  {default, 30},
+  {datatype, integer}
+]}.
+
+%% @doc Max Packets that Awaiting PUBREL, 0 means no limit
+{mapping, "mqtt.session.max_awaiting_rel", "emqttd.mqtt_session", [
+  {default, 0},
+  {datatype, integer}
+]}.
+
+%% @doc Statistics Collection Interval(seconds)
+{mapping, "mqtt.session.collect_interval", "emqttd.mqtt_session", [
+  {default, 0},
+  {datatype, integer}
+]}.
+
+%% @doc Session expired after...
+{mapping, "mqtt.session.expired_after", "emqttd.mqtt_session", [
+  {default, "2d"},
+  {datatype, {duration, s}}
+]}.
+
+{translation, "emqttd.mqtt_session", fun(Conf) ->
+  [{max_inflight, cuttlefish:conf_get("mqtt.session.max_inflight", Conf)},
+   {unack_retry_interval, cuttlefish:conf_get("mqtt.session.unack_retry_interval", Conf)},
+   {await_rel_timeout, cuttlefish:conf_get("mqtt.session.await_rel_timeout", Conf)},
+   {max_awaiting_rel, cuttlefish:conf_get("mqtt.session.max_awaiting_rel", Conf)},
+   {collect_interval, cuttlefish:conf_get("mqtt.session.collect_interval", Conf)},
+   {expired_after, cuttlefish:conf_get("mqtt.session.expired_after", Conf)}]
+end}.
+
+%%--------------------------------------------------------------------
+%% MQTT Queue
+%%--------------------------------------------------------------------
+
+%% @doc Type: simple | priority
+{mapping, "mqtt.queue.type", "emqttd.mqtt_queue", [
+  {default, simple},
+  {datatype, atom}
+]}.
+
+%% @doc Topic Priority: 0~255, Default is 0
+{mapping, "mqtt.queue.priority", "emqttd.mqtt_queue", [
+  {default, ""},
+  {datatype, string},
+  hidden
+]}.
+
+%% @doc Max queue length. Enqueued messages when persistent client disconnected, or inflight window is full.
+{mapping, "mqtt.queue.max_length", "emqttd.mqtt_queue", [
+  {default, infinity},
+  {datatype, [atom, integer]}
+]}.
+
+%% @doc Low-water mark of queued messages
+{mapping, "mqtt.queue.low_watermark", "emqttd.mqtt_queue", [
+  {default, "20%"},
+  {datatype, string},
+  hidden
+]}.
+
+%% @doc High-water mark of queued messages
+{mapping, "mqtt.queue.high_watermark", "emqttd.mqtt_queue", [
+  {default, "60%"},
+  {datatype, string},
+  hidden
+]}.
+
+%% @doc Queue Qos0 messages?
+{mapping, "mqtt.queue.qos0", "emqttd.mqtt_queue", [
+  {default, true},
+  {datatype, {enum, [true, false]}}
+]}.
+
+{translation, "emqttd.mqtt_queue", fun(Conf) ->
+  Parse = fun(S) ->
+			{match, [N]} = re:run(S, "^([0-9]+)%$", [{capture, all_but_first, list}]),
+			list_to_integer(N) / 100
+	      end,
+  Opts = [{type, cuttlefish:conf_get("mqtt.queue.type", Conf, simple)},
+          {max_length, cuttlefish:conf_get("mqtt.queue.max_length", Conf)},
+          {low_watermark, Parse(cuttlefish:conf_get("mqtt.queue.low_watermark", Conf))},
+          {high_watermark, Parse(cuttlefish:conf_get("mqtt.queue.high_watermark", Conf))},
+          {queue_qos0, cuttlefish:conf_get("mqtt.queue.qos0", Conf)}],
+  case cuttlefish:conf_get("mqtt.queue.priority", Conf) of
+    undefined -> Opts;
+    V -> [{priority,
+			 [begin [T, P] = string:tokens(S, "="),
+					{T, list_to_integer(P)}
+		      end || S <- string:tokens(V, ",")]}|Opts]
+  end
+end}.
+
+%%--------------------------------------------------------------------
+%% MQTT Broker
+%%--------------------------------------------------------------------
+{mapping, "mqtt.broker.sys_interval", "emqttd.mqtt_broker", [
+  {default, 60},
+  {datatype, integer}
+]}.
+
+{translation, "emqttd.mqtt_broker", fun(Conf) ->
+  [{sys_interval, cuttlefish:conf_get("mqtt.broker.sys_interval", Conf)}]
+end}.
+
+%%--------------------------------------------------------------------
+%% MQTT PubSub
+%%--------------------------------------------------------------------
+{mapping, "mqtt.pubsub.pool_size", "emqttd.mqtt_pubsub", [
+  {default, 8},
+  {datatype, integer}
+]}.
+
+{mapping, "mqtt.pubsub.by_clientid", "emqttd.mqtt_pubsub", [
+  {default, true},
+  {datatype, {enum, [true, false]}}
+]}.
+
+{mapping, "mqtt.pubsub.async", "emqttd.mqtt_pubsub", [
+  {default, true},
+  {datatype, {enum, [true, false]}},
+  hidden
+]}.
+
+{translation, "emqttd.mqtt_pubsub", fun(Conf) ->
+  [{pool_size, cuttlefish:conf_get("mqtt.pubsub.pool_size", Conf)},
+   {by_clientid, cuttlefish:conf_get("mqtt.pubsub.by_clientid", Conf)},
+   {async, cuttlefish:conf_get("mqtt.pubsub.async", Conf)}]
+end}.
+
+%%--------------------------------------------------------------------
+%% MQTT Bridge
+%%--------------------------------------------------------------------
+{mapping, "mqtt.bridge.max_queue_len", "emqttd.mqtt_bridge", [
+  {default, 10000},
+  {datatype, integer}
+]}.
+
+{mapping, "mqtt.bridge.ping_down_interval", "emqttd.mqtt_bridge", [
+  {default, 1},
+  {datatype, integer}
+]}.
+
+{translation, "emqttd.mqtt_bridge", fun(Conf) ->
+  [{max_queue_len, cuttlefish:conf_get("mqtt.bridge.max_queue_len", Conf)},
+   {ping_down_interval, cuttlefish:conf_get("mqtt.bridge.ping_down_interval", Conf)}]
+end}.
+
+%%--------------------------------------------------------------------
+%% System Monitor
+%%--------------------------------------------------------------------
+
+%% @doc Long GC, don't monitor in production mode for:
+%% https://github.com/erlang/otp/blob/feb45017da36be78d4c5784d758ede619fa7bfd3/erts/emulator/beam/erl_gc.c#L421
 {mapping, "sysmon.long_gc", "emqttd.sysmon", [
   {default, false},
   {datatype, {enum, [true, false]}}
 ]}.
 
+%% @doc Long Schedule(ms)
 {mapping, "sysmon.long_schedule", "emqttd.sysmon", [
   {default, 1000},
   {datatype, integer}
 ]}.
 
+%% @doc Large Heap
 {mapping, "sysmon.large_heap", "emqttd.sysmon", [
-  {datatype, integer}
+  {default, "8MB"},
+  {datatype, bytesize}
 ]}.
 
+%% @doc Monitor Busy Port
 {mapping, "sysmon.busy_port", "emqttd.sysmon", [
   {default, false},
   {datatype, {enum, [true, false]}}
 ]}.
 
+%% @doc Monitor Busy Dist Port
 {mapping, "sysmon.busy_dist_port", "emqttd.sysmon", [
   {default, true},
   {datatype, {enum, [true, false]}}