Nginx – Client Request Body Buffered to Temporary File

nginx

I get the following error in my log files every time I try to upload a large file.

a client request body is buffered to a temporary file /var/lib/nginx/body/0000000001

Although the file uploads successfully, I always get the above error.

I increased the client_body_buffer_size to 1000m which is what I expect the largest file uploaded to be. However, this is was just a guess and although I don't get that error anymore I am wondering if this is an appropriate value to set for the client_body_buffer_size?

I would appreciate it if anyone can shed some light on this directive and how it should be used.

Best Answer

This is a warning, not an error. That's why it was prefaced with [warn] in the log.

It means that the size of the uploaded file was larger than the in-memory buffer reserved for uploads.

The directive client_body_buffer_size controls the size of that buffer.

If you can afford to have 1GB of RAM always reserved for the occasional file upload, then that's fine. It's a performance optimization to buffer the upload in RAM rather than in a temporary file on disk, though with such large uploads a couple of extra seconds probably doesn't matter much. If most of your uploads are small, then it's probably a waste.

In the end, only you can really make the decision as to what the appropriate size is.

Related Solutions

Nginx – How to correctly use the NginX location directive

See if that works:

location /phpmyadmin {
  alias /usr/share/phpmyadmin;
  index index.php index.html;
}

location ~ .php$ {
  fastcgi_pass 127.0.0.1:9000;
  fastcgi_index index.php;
  fastcgi_param SCRIPT_FILENAME /usr/share/$fastcgi_script_name;
  include /etc/nginx/fastcgi_params;
  fastcgi_param SERVER_NAME $host;
}

Your config is not wrong or anything. Using root inside location blocks is not advised because if you get a lot of location blocks it starts to get messy (so it's better to have one root per server block) but that's not your case, and the fastcgi settings are usually done on a broader manner (for all php requests).

Nginx Reverse Proxy – Upstream Response Buffered to a Temporary File

How can I remove the [warn] and avoid buffering responses? Is it better to turn off proxy_buffering or set proxy_max_temp_file_size to 0? Why?

You should set proxy_max_temp_file_size to 0 in order to remove it. The proxy_buffering directive isn't directly related to the warning. You can switch it off to stop any buffering at all but that isn't recommended in general (unless it's needed for Comet).

If nginx buffers a response when does it serve the buffered response, to whom and why?

It serves the response immediately, but a client usually has a much slower connection and can't consume the response data as fast as it is produced by your application. Nginx tries to buffer the whole response in order to release your application ASAP.

Why nginx turns proxy_buffering on by default and then [warn]s you if it actually buffers a response?

As I already mentioned, the proxy_buffering isn't directly related to the warning. It's generally needed for optimized proxy operations and turning it off degrades performance and throughput.

Nginx only warns you when a response doesn't fit into configured memory buffers. You may ignore the warning if it's ok for you.

When does a response triggers that option? When it takes > than some seconds (how many?) to serve the response? Is this configurable?

It triggers when memory buffers are full. Please, look at the docs, the whole mechanism is explained: http://nginx.org/r/proxy_max_temp_file_size

You may want to increase memory buffers.