rails sendfile with nginx

nginx.conf

location ~ /data {
  internal;
  root /rails/app/path;
}

location / {
  #......

  proxy_set_header  Host              $http_host;
  proxy_set_header  X-Real-IP         $remote_addr;
  proxy_set_header  X-Forwarded-For   $proxy_add_x_forwarded_for;

  proxy_set_header  X-Sendfile-Type   X-Accel-Redirect;
  proxy_set_header  X-Accel-Mapping   /rails/app/path/data/=/data/;

  #......
}

maybe need this:

    proxy_headers_hash_bucket_size 1024;
    proxy_headers_hash_max_size 512;