diff --git a/oml/server.py b/oml/server.py
index 89401d0..d0e997d 100644
--- a/oml/server.py
+++ b/oml/server.py
@@ -6,7 +6,6 @@ import sys
 import signal
 import time
 
-from tornado.httpserver import HTTPServer
 from tornado.ioloop import IOLoop
 from tornado.web import StaticFileHandler, Application
 
@@ -71,7 +70,6 @@ def shutdown():
         logger.debug('shutdown downloads')
         state.downloads.join()
     logger.debug('shutdown http_server')
-    state.http_server.stop()
     if state.tasks:
         logger.debug('shutdown tasks')
         state.tasks.join()
@@ -135,8 +133,9 @@ def run():
     ]
 
     setup.create_db()
-    http_server = HTTPServer(Application(handlers, **options))
-    http_server.listen(settings.server['port'], settings.server['address'])
+    http_server = Application(handlers, **options)
+    max_buffer_size = 2*1024*1024*1024
+    http_server.listen(settings.server['port'], settings.server['address'], max_buffer_size=max_buffer_size)
 
     if PID:
         with open(PID, 'w') as pid:
diff --git a/oml/websocket.py b/oml/websocket.py
index 466adeb..7e468f2 100644
--- a/oml/websocket.py
+++ b/oml/websocket.py
@@ -57,11 +57,10 @@ class Handler(WebSocketHandler):
 
     def post(self, event, data):
         message = json_dumps([event, data])
-        main = IOLoop.instance()
         if self.ws_connection is None:
             self.on_close()
         else:
-            main.add_callback(lambda: self.write_message(message))
+            state.main.add_callback(lambda: self.write_message(message))
 
 def trigger_event(event, data):
     #if len(state.websockets):