proxy buffering for media files?

[Maxim Dounin]

Hello!

On Tue, Sep 03, 2013 at 10:39:49AM -0400, bkosborne wrote:

> I'm working on a configuration for an nginx proxy that splits requests
> between two upstream servers. The main reason I'm using a proxy is for SSL
> termination and for redundancy between the two upstream servers. Each
> upstream server is just a simple nginx server with identical media files
> stored on each.
> 
> The largest media file requested is around 2.5 megabytes. There are files
> larger than that, but they are requested in byte-ranges from our CDN.
> 
> I'm wondering how I should configure proxy buffering here. I noticed that
> the default is set to on:
> http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering.
> But, I'm not sure the default values for the buffer sizes and whatnot are
> ideal. I've had proxy_buffering turned on for quite a while now, and have
> noticed that the proxy_temp directory has over 1 GB of data in it. To my
> understanding, this folder is used when the in-memory buffers cannot hold
> all of the data from the upstream, so it is written to disk.
> 
> 1. If I set proxy_buffering to off, does that mean that the proxy streams
> the data directly to the client without buffering anything? Essentially,
> that would mean that an nginx worker would be "busy" on both the upstream
> and proxy server for the entire duration of the request, correct?
> 
> 2. If I keep it on, does it make sense to change the buffer sizes so that
> the entire response from the upstream can fit into memory? I assume that
> would speed up the responses so that nothing is written to disk (slow). From
> my novice perspective, it seems counter intuitive to essentially read a file
> from upstream disk, write it to proxy disk, and then read it from proxy disk
> again.
> 
> What is a common use case for using proxy_buffering? Since it's a default
> option, I assume it's commonly used and for good reason. I'm just having a
> hard time applying the thought process to my specific setup.

As long as your backend servers aren't limited on the number of 
connections they can handle, best aproach would be to keep 
proxy_buffering switched on, but switch off disk buffering using 
proxy_max_temp_file_size.

See here for details:

http://nginx.org/r/proxy_max_temp_file_size

-- 
Maxim Dounin
http://nginx.org/en/donation.html