nginx: [emerg] "proxy_buffers" directive invalid value in /etc/nginx/sites-enabled/ - nginx

Question

I tried to restart nginx with command, but error occured.
When I run "sudo systemctl restart nginx", this happens.
Job for nginx.service failed because the control process exited with error code. See "systemctl status nginx.service" and "journalctl -xe" for details.
When I run "systemctl status nginx.service", this happens.
Mar 30 08:55:04 ip-172-31-22-186 nginx[2624]: nginx: [emerg] "proxy_buffers" directive invalid value in /etc/nginx/sites-enabled/...:19
Mar 30 08:55:04 ip-172-31-22-186 nginx[2624]: nginx: configuration file /etc/nginx/nginx.conf test failed
in nginx.conf file:
location / {
....
proxy_buffer_size 0M;
proxy_buffers 4 0M;
proxy_busy_buffers_size 0M;
client_max_body_size 0M;
}
is there a problem with the configuration here?

Answer 1

The proxy_buffers can not be configured like this. Based on what they are used for how how they are designed you can NOT set a buffer of 0m. This would set a memory size (page size) of 0M.
proxy_buffers
Sets the number and size of the buffers used for reading a response from the proxied server, for a single connection. By default, the buffer size is equal to one memory page. This is either 4K or 8K, depending on a platform.
The proxy buffer size is equal to a memory page. To find your current memory_page size type:
getconf PAGE_SIZE
This should return 4096(bytes) -> 4K.
So as you can see there is a reason why you can only use 4K or 8K depending on your system architecture.
We have a great blog post about proxying in general.
https://www.nginx.com/blog/performance-tuning-tips-tricks/
By turning proxy_buffering to on you can configure the proxy_buffers with the directives shown in the docs:
http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering