diff --git a/apps/emqttd/src/emqttd_mnesia.erl b/apps/emqttd/src/emqttd_mnesia.erl
index a06cd1b64..fbd74d74b 100644
--- a/apps/emqttd/src/emqttd_mnesia.erl
+++ b/apps/emqttd/src/emqttd_mnesia.erl
@@ -87,7 +87,7 @@ init_tables() ->
 %%------------------------------------------------------------------------------
 create_tables() ->
     %% trie tree tables
-    %%TODO: should use module 'mnesia_create' attribute...
+    %%TODO: should use module 'boot_mnesia' attribute...
     ok = emqttd_trie:mnesia(create),
     ok = emqttd_pubsub:mnesia(create),
     %% TODO: retained messages, this table should not be copied...
diff --git a/apps/emqttd/src/emqttd_retained.erl b/apps/emqttd/src/emqttd_msg_store.erl
similarity index 94%
rename from apps/emqttd/src/emqttd_retained.erl
rename to apps/emqttd/src/emqttd_msg_store.erl
index 5f48fce8f..a42f02170 100644
--- a/apps/emqttd/src/emqttd_retained.erl
+++ b/apps/emqttd/src/emqttd_msg_store.erl
@@ -20,13 +20,11 @@
 %%% SOFTWARE.
 %%%-----------------------------------------------------------------------------
 %%% @doc
-%%% emqttd retained messages.
+%%% MQTT retained message storage.
 %%% 
-%%% TODO: need to redesign later.
-%%%
 %%% @end
 %%%-----------------------------------------------------------------------------
--module(emqttd_retained).
+-module(emqttd_msg_store).
 
 -author('feng@slimpp.io').
 
@@ -35,23 +33,22 @@
 %% Mnesia callbacks
 -export([mnesia/1]).
 
--mnesia_create({mnesia, [create]}).
--mnesia_replicate({mnesia, [replicate]}).
+-boot_mnesia({mnesia, [boot]}).
+-copy_mnesia({mnesia, [copy]}).
 
 %% API Function Exports
--export([retain/1, redeliver/2]).
+-export([retain/1, read/2, delete/1]).
 
-mnesia(create) ->
+mnesia(boot) ->
     ok = emqttd_mnesia:create_table(message, [
                 {type, ordered_set},
                 {ram_copies, [node()]},
                 {record_name, mqtt_message},
                 {attributes, record_info(fields, mqtt_message)}]);
-mnesia(replicate) ->
+
+mnesia(copy) ->
     ok = emqttd_mnesia:copy_table(message).
 
-
-
 %% @doc retain message.
 -spec retain(mqtt_message()) -> ok | ignore.
 retain(#mqtt_message{retain = false}) -> ignore;
diff --git a/apps/emqttd/src/emqttd_pubsub.erl b/apps/emqttd/src/emqttd_pubsub.erl
index c5a6916c4..c1177a6ee 100644
--- a/apps/emqttd/src/emqttd_pubsub.erl
+++ b/apps/emqttd/src/emqttd_pubsub.erl
@@ -41,8 +41,8 @@
 %% Mnesia Callbacks
 -export([mnesia/1]).
 
--mnesia_create({mnesia, [create]}).
--mnesia_replicate({mnesia, [replicate]}).
+-boot_mnesia({mnesia, [boot]}).
+-copy_mnesia({mnesia, [copy]}).
 
 %% API Exports 
 -export([start_link/0]).
@@ -63,7 +63,7 @@
 %%%=============================================================================
 %%% Mnesia callbacks
 %%%=============================================================================
-mnesia(create) ->
+mnesia(boot) ->
     %% topic table
     ok = emqttd_mnesia:create_table(topic, [
                 {type, bag},
@@ -79,7 +79,7 @@ mnesia(create) ->
                 {index, [subpid]},
                 {local_content, true}]);
 
-mnesia(replicate) ->
+mnesia(copy) ->
     ok = emqttd_mnesia:copy_table(topic),
     ok = emqttd_mnesia:copy_table(subscriber).
 
diff --git a/apps/emqttd/src/emqttd_trie.erl b/apps/emqttd/src/emqttd_trie.erl
index 6938bb1a5..b87cb23d2 100644
--- a/apps/emqttd/src/emqttd_trie.erl
+++ b/apps/emqttd/src/emqttd_trie.erl
@@ -33,8 +33,8 @@
 %% Mnesia Callbacks
 -export([mnesia/1]).
 
--mnesia_create({mnesia, [create]}).
--mnesia_replicate({mnesia, [replicate]}).
+-boot_mnesia({mnesia, [boot]}).
+-copy_mnesia({mnesia, [copy]}).
 
 %% Trie API
 -export([insert/1, find/1, delete/1]).
@@ -67,8 +67,8 @@
 %%
 %% @end
 %%------------------------------------------------------------------------------
--spec mnesia(create | replicate) -> ok.
-mnesia(create) ->
+-spec mnesia(boot | copy) -> ok.
+mnesia(boot) ->
     %% trie tree tables
     ok = emqttd_mnesia:create_table(trie, [
                 {ram_copies, [node()]},
@@ -85,7 +85,7 @@ mnesia(create) ->
 %%
 %% @end
 %%------------------------------------------------------------------------------
-mnesia(replicate) ->
+mnesia(copy) ->
     ok = emqttd_mnesia:copy_table(trie),
     ok = emqttd_mnesia:copy_table(trie_node).