nginx warn an upstream response is buffered to a temporary file /var/cache/nginx/proxy_temp/ while reading upstream

最近管理的nginx發現大量的error log，log內容如下：

an upstream response is buffered to a temporary file /var/cache/nginx/proxy_temp/0/52/0002923520 while reading upstream

從這條error日志來看是nginx某一塊的buffer設置的太小，而response（包含response header和response body）導致response結果不得不臨時寫到文件中。

可以修改的配置參數

  client_header_buffer_size 128k;
  client_body_buffer_size 1m;
  proxy_buffer_size 32k;
  proxy_buffers 64 32k;
  proxy_busy_buffers_size 1m;
  proxy_temp_file_write_size 512k;

經過這樣的配置調整之后，基本上沒有這樣的error日志了。

關於這幾個配置的官方文檔鏈接如下

http://nginx.org/en/docs/http/ngx_http_core_module.html#directives

http://nginx.org/en/docs/http/ngx_http_proxy_module.html#directives