diff --git a/apps/emqx/src/emqx_persistent_session_ds.erl b/apps/emqx/src/emqx_persistent_session_ds.erl
index a61bf37f9..76d42e8f0 100644
--- a/apps/emqx/src/emqx_persistent_session_ds.erl
+++ b/apps/emqx/src/emqx_persistent_session_ds.erl
@@ -46,7 +46,7 @@
 
 %% FIXME
 -define(DS_SHARD, <<"local">>).
--define(DEFAULT_KEYSPACE, <<"#">>).
+-define(DEFAULT_KEYSPACE, default).
 
 -define(WHEN_ENABLED(DO),
     case is_store_enabled() of
@@ -60,10 +60,16 @@
 init() ->
     ?WHEN_ENABLED(begin
         ok = emqx_ds:ensure_shard(
-            ?DS_SHARD,
             ?DEFAULT_KEYSPACE,
+            ?DS_SHARD,
             #{
-                dir => filename:join([emqx:data_dir(), ds, messages, ?DS_SHARD])
+                dir => filename:join([
+                    emqx:data_dir(),
+                    ds,
+                    messages,
+                    atom_to_binary(?DEFAULT_KEYSPACE),
+                    ?DS_SHARD
+                ])
             }
         ),
         ok = emqx_persistent_session_ds_router:init_tables(),
diff --git a/apps/emqx_durable_storage/src/emqx_ds.erl b/apps/emqx_durable_storage/src/emqx_ds.erl
index 8e6f5535d..cf93e97a0 100644
--- a/apps/emqx_durable_storage/src/emqx_ds.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds.erl
@@ -78,7 +78,7 @@
 %% Parsed topic:
 -type topic() :: list(binary()).
 
--type keyspace() :: binary().
+-type keyspace() :: atom().
 -type shard() :: binary().
 
 %% Timestamp
@@ -98,10 +98,10 @@
 %% API funcions
 %%================================================================================
 
--spec ensure_shard(shard(), keyspace(), emqx_ds_storage_layer:options()) ->
+-spec ensure_shard(keyspace(), shard(), emqx_ds_storage_layer:options()) ->
     ok | {error, _Reason}.
-ensure_shard(Shard, Keyspace, Options) ->
-    case emqx_ds_storage_layer_sup:start_shard(Shard, Keyspace, Options) of
+ensure_shard(Keyspace, Shard, Options) ->
+    case emqx_ds_storage_layer_sup:start_shard(Keyspace, Shard, Options) of
         {ok, _Pid} ->
             ok;
         {error, {already_started, _Pid}} ->
diff --git a/apps/emqx_durable_storage/src/emqx_ds_message_storage_bitmask.erl b/apps/emqx_durable_storage/src/emqx_ds_message_storage_bitmask.erl
index ae292452e..b537e8f0e 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_message_storage_bitmask.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_message_storage_bitmask.erl
@@ -173,8 +173,8 @@
 -opaque schema() :: #schema{}.
 
 -record(db, {
-    shard :: emqx_ds:shard(),
     keyspace :: emqx_ds:keyspace(),
+    shard :: emqx_ds:shard(),
     handle :: rocksdb:db_handle(),
     cf :: rocksdb:cf_handle(),
     keymapper :: keymapper(),
@@ -236,19 +236,19 @@ create_new(DBHandle, GenId, Options) ->
 
 %% Reopen the database
 -spec open(
-    emqx_ds:shard(),
     emqx_ds:keyspace(),
+    emqx_ds:shard(),
     rocksdb:db_handle(),
     emqx_ds_storage_layer:gen_id(),
     emqx_ds_storage_layer:cf_refs(),
     schema()
 ) ->
     db().
-open(Shard, Keyspace, DBHandle, GenId, CFs, #schema{keymapper = Keymapper}) ->
+open(Keyspace, Shard, DBHandle, GenId, CFs, #schema{keymapper = Keymapper}) ->
     {value, {_, CFHandle}} = lists:keysearch(data_cf(GenId), 1, CFs),
     #db{
-        shard = Shard,
         keyspace = Keyspace,
+        shard = Shard,
         handle = DBHandle,
         cf = CFHandle,
         keymapper = Keymapper
diff --git a/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl b/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl
index f34d508d9..1aee14f43 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl
@@ -7,7 +7,7 @@
 
 %% API:
 -export([start_link/3]).
--export([create_generation/3]).
+-export([create_generation/4]).
 
 -export([store/5]).
 -export([delete/4]).
@@ -99,7 +99,7 @@
 %% 3. `inplace_update_support`?
 -define(ITERATOR_CF_OPTS, []).
 
--define(REF(Shard), {via, gproc, {n, l, {?MODULE, Shard}}}).
+-define(REF(Keyspace, Shard), {via, gproc, {n, l, {?MODULE, Keyspace, Shard}}}).
 
 %%================================================================================
 %% Callbacks
@@ -109,8 +109,8 @@
     {_Schema, cf_refs()}.
 
 -callback open(
-    emqx_ds:shard(),
     emqx_ds:keyspace(),
+    emqx_ds:shard(),
     rocksdb:db_handle(),
     gen_id(),
     cf_refs(),
@@ -143,15 +143,17 @@
 %% API funcions
 %%================================================================================
 
--spec start_link(emqx_ds:shard(), emqx_ds:keyspace(), emqx_ds_storage_layer:options()) ->
+-spec start_link(emqx_ds:keyspace(), emqx_ds:shard(), emqx_ds_storage_layer:options()) ->
     {ok, pid()}.
-start_link(Shard, Keyspace, Options) ->
-    gen_server:start_link(?REF(Shard), ?MODULE, {Shard, Keyspace, Options}, []).
+start_link(Keyspace, Shard, Options) ->
+    gen_server:start_link(?REF(Keyspace, Shard), ?MODULE, {Keyspace, Shard, Options}, []).
 
--spec create_generation(emqx_ds:shard(), emqx_ds:time(), emqx_ds_conf:backend_config()) ->
+-spec create_generation(
+    emqx_ds:keyspace(), emqx_ds:shard(), emqx_ds:time(), emqx_ds_conf:backend_config()
+) ->
     {ok, gen_id()} | {error, nonmonotonic}.
-create_generation(Shard, Since, Config = {_Module, _Options}) ->
-    gen_server:call(?REF(Shard), {create_generation, Since, Config}).
+create_generation(Keyspace, Shard, Since, Config = {_Module, _Options}) ->
+    gen_server:call(?REF(Keyspace, Shard), {create_generation, Since, Config}).
 
 -spec store(emqx_ds:shard(), emqx_guid:guid(), emqx_ds:time(), emqx_ds:topic(), binary()) ->
     ok | {error, _}.
@@ -258,9 +260,9 @@ foldl_iterator_prefix(Shard, KeyPrefix, Fn, Acc) ->
 %% behaviour callbacks
 %%================================================================================
 
-init({Shard, Keyspace, Options}) ->
+init({Keyspace, Shard, Options}) ->
     process_flag(trap_exit, true),
-    {ok, S0} = open_db(Shard, Keyspace, Options),
+    {ok, S0} = open_db(Keyspace, Shard, Options),
     S = ensure_current_generation(S0),
     ok = populate_metadata(S),
     {ok, S}.
@@ -342,9 +344,10 @@ create_gen(GenId, Since, {Module, Options}, S = #s{db = DBHandle, cf_generations
     },
     {ok, Gen, S#s{cf_generations = NewCFs ++ CFs}}.
 
--spec open_db(emqx_ds:shard(), emqx_ds:keyspace(), options()) -> {ok, state()} | {error, _TODO}.
-open_db(Shard, Keyspace, Options) ->
-    DBDir = unicode:characters_to_list(maps:get(dir, Options, Shard)),
+-spec open_db(emqx_ds:keyspace(), emqx_ds:shard(), options()) -> {ok, state()} | {error, _TODO}.
+open_db(Keyspace, Shard, Options) ->
+    DefaultDir = filename:join([atom_to_binary(Keyspace), Shard]),
+    DBDir = unicode:characters_to_list(maps:get(dir, Options, DefaultDir)),
     DBOptions = [
         {create_if_missing, true},
         {create_missing_column_families, true}
@@ -382,9 +385,9 @@ open_db(Shard, Keyspace, Options) ->
 open_gen(
     GenId,
     Gen = #{module := Mod, data := Data},
-    #s{shard = Shard, keyspace = Keyspace, db = DBHandle, cf_generations = CFs}
+    #s{keyspace = Keyspace, shard = Shard, db = DBHandle, cf_generations = CFs}
 ) ->
-    DB = Mod:open(Shard, Keyspace, DBHandle, GenId, CFs, Data),
+    DB = Mod:open(Keyspace, Shard, DBHandle, GenId, CFs, Data),
     Gen#{data := DB}.
 
 -spec open_next_iterator(iterator()) -> {ok, iterator()} | {error, _Reason} | none.
diff --git a/apps/emqx_durable_storage/src/emqx_ds_storage_layer_sup.erl b/apps/emqx_durable_storage/src/emqx_ds_storage_layer_sup.erl
index cf84c905c..6ae651e74 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_storage_layer_sup.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_storage_layer_sup.erl
@@ -25,10 +25,10 @@
 start_link() ->
     supervisor:start_link({local, ?SUP}, ?MODULE, []).
 
--spec start_shard(emqx_ds:shard(), emqx_ds:keyspace(), emqx_ds_storage_layer:options()) ->
+-spec start_shard(emqx_ds:keyspace(), emqx_ds:shard(), emqx_ds_storage_layer:options()) ->
     supervisor:startchild_ret().
-start_shard(Shard, Keyspace, Options) ->
-    supervisor:start_child(?SUP, shard_child_spec(Shard, Keyspace, Options)).
+start_shard(Keyspace, Shard, Options) ->
+    supervisor:start_child(?SUP, shard_child_spec(Keyspace, Shard, Options)).
 
 -spec stop_shard(emqx_ds:shard()) -> ok | {error, _}.
 stop_shard(Shard) ->
@@ -52,12 +52,12 @@ init([]) ->
 %% Internal functions
 %%================================================================================
 
--spec shard_child_spec(emqx_ds:shard(), emqx_ds:keyspace(), emqx_ds_storage_layer:options()) ->
+-spec shard_child_spec(emqx_ds:keyspace(), emqx_ds:shard(), emqx_ds_storage_layer:options()) ->
     supervisor:child_spec().
-shard_child_spec(Shard, Keyspace, Options) ->
+shard_child_spec(Keyspace, Shard, Options) ->
     #{
         id => Shard,
-        start => {emqx_ds_storage_layer, start_link, [Shard, Keyspace, Options]},
+        start => {emqx_ds_storage_layer, start_link, [Keyspace, Shard, Options]},
         shutdown => 5_000,
         restart => permanent,
         type => worker
diff --git a/apps/emqx_durable_storage/test/emqx_ds_storage_layer_SUITE.erl b/apps/emqx_durable_storage/test/emqx_ds_storage_layer_SUITE.erl
index e19c83dc1..caceaa1b3 100644
--- a/apps/emqx_durable_storage/test/emqx_ds_storage_layer_SUITE.erl
+++ b/apps/emqx_durable_storage/test/emqx_ds_storage_layer_SUITE.erl
@@ -34,7 +34,7 @@
 %% Smoke test for opening and reopening the database
 t_open(_Config) ->
     ok = emqx_ds_storage_layer_sup:stop_shard(?SHARD),
-    {ok, _} = emqx_ds_storage_layer_sup:start_shard(?SHARD, ?KEYSPACE, #{}).
+    {ok, _} = emqx_ds_storage_layer_sup:start_shard(?KEYSPACE, ?SHARD, #{}).
 
 %% Smoke test of store function
 t_store(_Config) ->
@@ -137,16 +137,16 @@ t_iterate_long_tail_wildcard(_Config) ->
     ).
 
 t_create_gen(_Config) ->
-    {ok, 1} = emqx_ds_storage_layer:create_generation(?SHARD, 5, ?DEFAULT_CONFIG),
+    {ok, 1} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 5, ?DEFAULT_CONFIG),
     ?assertEqual(
         {error, nonmonotonic},
-        emqx_ds_storage_layer:create_generation(?SHARD, 1, ?DEFAULT_CONFIG)
+        emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 1, ?DEFAULT_CONFIG)
     ),
     ?assertEqual(
         {error, nonmonotonic},
-        emqx_ds_storage_layer:create_generation(?SHARD, 5, ?DEFAULT_CONFIG)
+        emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 5, ?DEFAULT_CONFIG)
     ),
-    {ok, 2} = emqx_ds_storage_layer:create_generation(?SHARD, 10, ?COMPACT_CONFIG),
+    {ok, 2} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 10, ?COMPACT_CONFIG),
     Topics = ["foo/bar", "foo/bar/baz"],
     Timestamps = lists:seq(1, 100),
     [
@@ -155,9 +155,9 @@ t_create_gen(_Config) ->
     ].
 
 t_iterate_multigen(_Config) ->
-    {ok, 1} = emqx_ds_storage_layer:create_generation(?SHARD, 10, ?COMPACT_CONFIG),
-    {ok, 2} = emqx_ds_storage_layer:create_generation(?SHARD, 50, ?DEFAULT_CONFIG),
-    {ok, 3} = emqx_ds_storage_layer:create_generation(?SHARD, 1000, ?DEFAULT_CONFIG),
+    {ok, 1} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 10, ?COMPACT_CONFIG),
+    {ok, 2} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 50, ?DEFAULT_CONFIG),
+    {ok, 3} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 1000, ?DEFAULT_CONFIG),
     Topics = ["foo/bar", "foo/bar/baz", "a", "a/bar"],
     Timestamps = lists:seq(1, 100),
     _ = [
@@ -181,9 +181,9 @@ t_iterate_multigen(_Config) ->
 
 t_iterate_multigen_preserve_restore(_Config) ->
     ReplayID = atom_to_binary(?FUNCTION_NAME),
-    {ok, 1} = emqx_ds_storage_layer:create_generation(?SHARD, 10, ?COMPACT_CONFIG),
-    {ok, 2} = emqx_ds_storage_layer:create_generation(?SHARD, 50, ?DEFAULT_CONFIG),
-    {ok, 3} = emqx_ds_storage_layer:create_generation(?SHARD, 100, ?DEFAULT_CONFIG),
+    {ok, 1} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 10, ?COMPACT_CONFIG),
+    {ok, 2} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 50, ?DEFAULT_CONFIG),
+    {ok, 3} = emqx_ds_storage_layer:create_generation(?KEYSPACE, ?SHARD, 100, ?DEFAULT_CONFIG),
     Topics = ["foo/bar", "foo/bar/baz", "a/bar"],
     Timestamps = lists:seq(1, 100),
     TopicFilter = "foo/#",
@@ -264,17 +264,17 @@ end_per_suite(_Config) ->
 
 init_per_testcase(TC, Config) ->
     ok = set_keyspace_config(keyspace(TC), ?DEFAULT_CONFIG),
-    {ok, _} = emqx_ds_storage_layer_sup:start_shard(shard(TC), keyspace(TC), #{}),
+    {ok, _} = emqx_ds_storage_layer_sup:start_shard(keyspace(TC), shard(TC), #{}),
     Config.
 
 end_per_testcase(TC, _Config) ->
     ok = emqx_ds_storage_layer_sup:stop_shard(shard(TC)).
 
 keyspace(TC) ->
-    list_to_binary(lists:concat([?MODULE, "_", TC])).
+    list_to_atom(lists:concat([?MODULE, "_", TC])).
 
 shard(TC) ->
-    <<(keyspace(TC))/binary, "_shard">>.
+    <<(atom_to_binary(keyspace(TC)))/binary, "_shard">>.
 
 set_keyspace_config(Keyspace, Config) ->
     ok = application:set_env(emqx_ds, keyspace_config, #{Keyspace => Config}).
diff --git a/apps/emqx_durable_storage/test/props/prop_replay_message_storage.erl b/apps/emqx_durable_storage/test/props/prop_replay_message_storage.erl
index e1981888b..14e76d707 100644
--- a/apps/emqx_durable_storage/test/props/prop_replay_message_storage.erl
+++ b/apps/emqx_durable_storage/test/props/prop_replay_message_storage.erl
@@ -10,8 +10,8 @@
 -define(WORK_DIR, ["_build", "test"]).
 -define(RUN_ID, {?MODULE, testrun_id}).
 
--define(KEYSPACE, atom_to_binary(?MODULE)).
--define(SHARD, <<(?KEYSPACE)/binary, "_shard">>).
+-define(KEYSPACE, ?MODULE).
+-define(SHARD, <<(atom_to_binary(?KEYSPACE))/binary, "_shard">>).
 -define(GEN_ID, 42).
 
 %%--------------------------------------------------------------------