id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1814	"What should I do about the warning: ""upstream response is buffered to a temporary file""?"	anthony.mastrean.vaeit.com@…		"I'm one of those people that gets really concerned about warnings in my system's logs. I am seeing this one and not finding any reasonable advice about it.

> an upstream response is buffered to a temporary file

I've read the [https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering proxy_buffering] section and related directives documentation and can't really figure out...

 1. Why is this a warning, at all? (you support file buffering, is it bad?)
 2. What can I do about it? (should I increase memory buffers? the docs on proxy_buffer_size mention the size being carefully selected and only mention maybe reducing it)
 3. When should I disable [https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_max_temp_file_size file buffering], if at all?

I see that the warning was [https://github.com/nginx/nginx/blame/16ebfa999baac42341da6589ffaa8550b25acb2e/src/http/ngx_http_upstream.c#L3155 last changed] some 15 years ago, but I can't find any relevant comments or commit messages to explain any of these questions.

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I'm running nginx:stable-alpine in a Docker container (perhaps you have specific advice about file buffering in a container filesystem):

"	enhancement	closed	minor		documentation	1.16.x	invalid			Linux 0cc83ae1078e 3.10.0-957.12.2.el7.x86_64 #1 SMP Tue May 14 21:24:32 UTC 2019 x86_64 Linux	nginx version: nginx/1.16.0