Nginx understanding access log column

The column after “Response Code” (i.e. status) is “Bytes Sent”.

The default log format in nginx is called “combined”. It is the equivalent to the following configuration.

# nginx.conf
http {
  ...
  log_format combined '$remote_addr - $remote_user [$time_local] '
                      '"$request" $status $body_bytes_sent '
                      '"$http_referer" "$http_user_agent"';
  ...
}

Source: Module ngx_http_log_module