change client_body_buffer_size from 16K to 256K made the nginx logs size from 50M to 1G..

[meteor8488]

Hi Team,

I always use below configuration to record the post date of my webserver
(for security resaon)


http {

...

	log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
	'$status $body_bytes_sent "$http_referer" '
	'"$http_user_agent" "$http_x_forwarded_for"';
	log_format  plog  '$remote_addr - $remote_user [$time_local] "$request" '
	'$status $body_bytes_sent "$http_referer" '
	'"$http_user_agent" "$http_x_forwarded_for" "$request_body"';

	server {
		....

			location ~ \.php$ {
			try_files $uri =404;
			if ($request_method = POST){
				return                 484;
				break;
			}
			error_page               484 = @post;
			fastcgi_index  index.php;
			fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
			include        fastcgi_params;
			fastcgi_pass   backend;
		}
		location @post{
			internal;
			access_log /web/log/post.log  plog;
			try_files $uri =404;
			fastcgi_index  index.php;
			fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
			include        fastcgi_params;
			fastcgi_pass   backend;
			}
	}
}


And today I found that the size the post.log was almost 1G everyday, in the
past it's only 50M. The only thing I changed recently is the buffer_size

>From :

	client_header_buffer_size 64k;
	large_client_header_buffers 4 32k;
	client_body_buffer_size   16k;
	client_max_body_size 50m;
	fastcgi_buffer_size 64k;
	fastcgi_buffers 4 64k;
	fastcgi_busy_buffers_size 128k;
	fastcgi_temp_file_write_size 128k;

To:
	client_header_buffer_size 4k;
	large_client_header_buffers 4 32k;
	client_body_buffer_size   256k;
	client_max_body_size 8m;
	fastcgi_buffer_size 128k;
	fastcgi_buffers 256 16k;
	fastcgi_busy_buffers_size 256k;
	fastcgi_temp_file_write_size 256k;


Is that because I changed client_body_buffer_size  from 16K to 256K caused
the size change of the log file?
For now the client_body_buffer_size is big enough, when users upload a file,
then nginx will put it into the buffer instead of a temp file, and then also
write this file into post.log?  Am I right? 

If I'm right, then how can I exclude file upload from the post log? The
$request_uri for the upload is mod=swfupload.

Can anyone help?

Thanks

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,266793,266793#msg-266793