reduced shared buffer size

config/postgresql.conf

@@ -109,7 +109,7 @@ ssl = false                             # (change requires restart)
 # details: http://www.postgresql.org/docs/9.4/static/runtime-config-resource.html
 # http://www.postgresql.org/docs/9.4/static/runtime-config-wal.html
 # http://www.postgresql.org/docs/9.4/static/runtime-config-query.html
-shared_buffers = 2GB                    # min 128kB
+shared_buffers = 256MB                    # min 128kB
 work_mem = 64MB                                # min 64kB
 maintenance_work_mem = 512MB            # min 1MB
 checkpoint_segments = 64