add proxy_busy_buffers_size
diff --git a/nginx/files/proxy.conf b/nginx/files/proxy.conf
index c697f05..39f941c 100644
--- a/nginx/files/proxy.conf
+++ b/nginx/files/proxy.conf
@@ -61,6 +61,7 @@
       proxy_buffering on;
       proxy_buffers {{ site.proxy.buffer.get('number', 8) }} {{ site.proxy.buffer.get('size', 16) }}k;
       proxy_buffer_size {{ buffer_size }}k;
+      proxy_busy_buffers_size {{ site.proxy.buffer.get('busy', buffer_size) }}k;
       {%- else %}
       proxy_buffering off;
       {%- endif %}