question about proxy_buffers

[Jérôme Loyet]

2009/6/10 merlin corey <merlincorey at dc949.org>:
> I'm not Igor so I cannot be totally sure, but my understanding of it
> has always been 1- requests to the backend can use only one buffer and
> the response gets buffered to disk.  As such, I generally start out
> sites with log level info (might be too low) and try to tune down
> requests getting buffered if at all possible.  I also try to stick
> with magic numbers good for the architecture (so 8 and 16 based,
> generally).
>
Thx for the answer merlin,

I did some test. The request I make to nginx is proxied to the
backend. There is only one request made at the same time.
I request a 5Mo file.

First: with minimum buffers:
proxy_buffers 2 4k;

I have this in the log: 2009/06/11 19:40:05 [warn] 24607#0: *104 an
upstream response is buffered to a temporary file
/LIBRE/nginx/proxy_temp/0000000000 while reading upstream, ....

Then I set 10 buffers of 1Mo:
proxy_buffers 10 1m;
and nothing appears in logs.

This tells me that a request can use more than one buffer.

I'll set up small buffers but a large number:
proxy_buffers 2048 8k;

Is it too much ?

>
> 2009/6/9 Jérôme Loyet <jerome at loyet.net>:
>> Hi all,
>>
>> I'm not sure how proxy_buffers are used.
>>
>> 1- requests to the backend can use only one buffer. If the reponse is
>> bigger than one buffer, some part of the response is buffered to disk.
>> 2- requests to the backen can use multiple buffers. If the response is
>> bigger than on buffer, nginx will use more buffers (if available of
>> course).
>>
>> So depending on the answer, I would use :
>> 1- big buffers so that 80% of the requests can feet in on buffer. And
>> enough buffers so that 80% of the requests can be buffered
>> 2- small buffers and a lots of buffers
>>
>> don't know what to use :) any clue ?
>>
>> thx
>> ++ jerome
>>
>>
>
>