diff --git a/docker/docker-compose-verne.yml b/docker/docker-compose-verne.yml
index 00f815f4..84923b02 100644
--- a/docker/docker-compose-verne.yml
+++ b/docker/docker-compose-verne.yml
@@ -233,6 +233,8 @@ services:
       DOCKER_VERNEMQ_PLUGINS__VMQ_ACL: "off"
       DOCKER_VERNEMQ_PLUGINS__MFX_AUTH: "on"
       DOCKER_VERNEMQ_PLUGINS__MFX_AUTH__PATH: /mainflux/_build/default
+      DOCKER_VERNEMQ_LOG__CONSOLE__LEVEL: warning
+      MF_MQTT_VERNEMQ_GRPC_POOL_SIZE: 1000
     ports:
       - ${MF_MQTT_ADAPTER_PORT}:${MF_MQTT_ADAPTER_PORT}
       - ${MF_MQTT_ADAPTER_WS_PORT}:${MF_MQTT_ADAPTER_WS_PORT}
diff --git a/mqtt/verne/src/mfx_auth_sup.erl b/mqtt/verne/src/mfx_auth_sup.erl
index 95675e53..d7c6eddb 100644
--- a/mqtt/verne/src/mfx_auth_sup.erl
+++ b/mqtt/verne/src/mfx_auth_sup.erl
@@ -23,7 +23,15 @@ start_link() ->
 %% ===================================================================
 
 init([]) ->
-    SizeArgs = [{size, 10}, {max_overflow, 10}],
+    PoolSize = case os:getenv("MF_MQTT_VERNEMQ_GRPC_POOL_SIZE") of
+        false ->
+            10;
+        PoolSizeEnv ->
+            {PoolSizeInt, _PoolSizeRest} = string:to_integer(PoolSizeEnv),
+            PoolSizeInt
+    end,
+
+    SizeArgs = [{size, PoolSize}, {max_overflow, PoolSize * 1.5}],
     PoolArgs = [{name, {local, grpc_pool}}, {worker_module, mfx_grpc}],
     WorkerArgs = [],
     PoolSpec = poolboy:child_spec(grpc_pool, PoolArgs ++ SizeArgs, WorkerArgs),
diff --git a/mqtt/verne/src/mfx_grpc.erl b/mqtt/verne/src/mfx_grpc.erl
index e4fa38ce..69819123 100644
--- a/mqtt/verne/src/mfx_grpc.erl
+++ b/mqtt/verne/src/mfx_grpc.erl
@@ -16,7 +16,6 @@
 
 init(_Args) ->
     error_logger:info_msg("mfx_grpc genserver has started (~w)~n", [self()]),
-
     [{_, GrpcUrl}] = ets:lookup(mfx_cfg, grpc_url),
     {ok, {_, _, GrpcHost, GrpcPort, _, _}} = http_uri:parse(GrpcUrl),
     error_logger:info_msg("grpc host: ~p,  port: ~p", [GrpcHost, GrpcPort]),
diff --git a/mqtt/verne/src/mfx_nats.erl b/mqtt/verne/src/mfx_nats.erl
index def0b82c..5248b564 100644
--- a/mqtt/verne/src/mfx_nats.erl
+++ b/mqtt/verne/src/mfx_nats.erl
@@ -4,6 +4,7 @@
     start_link/0,
     init/1,
     publish/2,
+    handle_call/3,
     handle_cast/2,
     handle_info/2,
     terminate/2,
@@ -35,6 +36,11 @@ publish(Subject, Message) ->
     error_logger:info_msg("mfx_nats genserver publish ~p ~p", [Subject, Message]),
     gen_server:cast(?MODULE, {publish, Subject, Message}).
 
+% Currently unused, but kept to avoid compiler warnings (it expects handle_call/3 in the gen_server)
+handle_call(Name, _From, _State) ->
+    Reply = lists:flatten(io_lib:format("Hello ~s from mfx_nats genserver", [Name])),
+    {reply, Reply, _State}.
+
 handle_cast({publish, Subject, Message}, #state{conn = NatsConn} = State) ->
     error_logger:info_msg("mfx_nats genserver cast ~p ~p ~p", [Subject, NatsConn, Message]),
     nats:pub(NatsConn, Subject, #{payload => Message}),
diff --git a/mqtt/verne/src/mfx_redis.erl b/mqtt/verne/src/mfx_redis.erl
index 0688f4a0..74bbcb60 100644
--- a/mqtt/verne/src/mfx_redis.erl
+++ b/mqtt/verne/src/mfx_redis.erl
@@ -5,6 +5,7 @@
     start_link/0,
     init/1,
     publish/1,
+    handle_call/3,
     handle_cast/2,
     handle_info/2,
     terminate/2
@@ -28,10 +29,14 @@ init(_Args) ->
 publish(Message) ->
     gen_server:cast(?MODULE, {publish, Message}).
 
+% Currently unused, but kept to avoid compiler warnings (it expects handle_call/3 in the gen_server)
+handle_call(Name, _From, _State) ->
+    Reply = lists:flatten(io_lib:format("Hello ~s from mfx_redis genserver", [Name])),
+    {reply, Reply, _State}.
+
 handle_cast({publish, Message}, #state{conn = RedisConn} = State) ->
-    [{redis_conn, Conn}] = ets:lookup(mfx_cfg, redis_conn),
     error_logger:info_msg("mfx_redis genserver cast ~p ~p", [RedisConn, Message]),
-    eredis:q(Conn, ["XADD" | Message]),
+    eredis:q(RedisConn, ["XADD" | Message]),
     {noreply, State}.
 
 handle_info(_Info, State) ->
diff --git a/tools/mqtt-bench/templates/config.toml b/tools/mqtt-bench/templates/config.toml
index d64a1e27..11895618 100644
--- a/tools/mqtt-bench/templates/config.toml
+++ b/tools/mqtt-bench/templates/config.toml
@@ -6,7 +6,7 @@
   size = 100
   format = "text"
   qos = 2
-  retain = true
+  retain = false
 
   [mqtt.tls]
   mtls = false
@@ -14,8 +14,8 @@
   ca = "ca.crt"
 
 [test]
-pubs = 3
-subs = 1
+pubs = 100
+subs = 30
 count = 100
 
 [log]