參考：Nginx 作為反向代理優化要點proxy_buffering

利用nginx做反向代理時，配置文件可以參考下面的配置：

user  nginx;
worker_processes  2;

error_log  logs/error.log warn;
pid        logs/nginx.pid;
events {
    worker_connections  10240;
    multi_accept        on;
    use                 epoll;
}
http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  logs/access.log  main;
    sendfile        on;
    tcp_nopush     on;
    tcp_nodelay        on;
    underscores_in_headers on;#off 表示如果header name中包含下劃線,則忽略掉,部署後就獲取不到 on則相反
    keepalive_timeout  240;
    server_tokens off; #隱藏版本號
    send_timeout 10m;
    client_header_buffer_size 256k;
    client_max_body_size 1000m;
    client_body_timeout 10m;
    client_header_timeout 10m;
    large_client_header_buffers 8 64k;
    client_body_buffer_size 20m;

    fastcgi_buffers 6 256k;
    fastcgi_buffer_size 1024k;
    fastcgi_busy_buffers_size 1024k;
    proxy_request_buffering off;
    proxy_buffering    off; #開啟從後端被代理服務器的響應內容緩沖
    proxy_buffer_size  128k; #設置緩沖區的大小和數量
    proxy_buffers 100  128k;
    proxy_busy_buffers_size 128k;
	
	upstream NAME {
        server host:port;
    }
    upstream NAME_SSL {
        server host:443;
    }
	
    server {
        listen       80;
        server_name  a.example.com;
        charset utf8;
        ignore_invalid_headers off;
	error_page  404  403 =https://a.example.com/404.html;
	location / {
            include conf.d/deny_appid.conf; #location自定義配置
            proxy_pass http://NAME/;
            proxy_redirect  off;
            proxy_set_header Host $http_host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Cookie $http_cookie;
            chunked_transfer_encoding  off;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
        }
    }
    server {
        listen       443 ssl;
        server_name  a.example.com;
        ignore_invalid_headers off;
        charset utf8;

        ssl_certificate      example.com.crt;
        ssl_certificate_key  example.com.key;

        ssl_session_cache    shared:SSL:1m;
        ssl_session_timeout  5m;

        ssl_ciphers  HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers  on;
        error_page  404  403 =https://a.example.com/404.html;
        location / {
            include conf.d/deny_appid.conf;
            proxy_pass https://NAME_SSL/;
            proxy_ssl_session_reuse off;
            proxy_redirect  off;
            proxy_set_header Host $http_host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Cookie $http_cookie;
            chunked_transfer_encoding  off;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
        }
    }
}

nginx+tomcat 報錯：『an upstream response is buffered to a temporary file 』

參考鏈接：http://blog.51cto.com/11413817/1950467

nginx的an upstream response is buffered to a temporary file報錯

client_header_buffer_size 256k; 
把原來的32k改為256k

nginx fastcgi_buffers to an upstream response is buffered to a temporary file

fastcgi_buffers 16 16k;
指定本地需要用多少和多大的緩沖區來緩沖FastCGI的應答，如上所示，如果一個php腳本所產生的頁面大小為256k，則會為其分配16個16k的緩沖區來緩存，如果大於256k，增大於256k的部分會緩存到fastcgi_temp指定的路徑中，當然這對服務器負載來說是不明智的方案，因為內存中處理數據速度要快於硬盤，通常這個值的設置應該選擇一個你的站點中的php腳本所產生的頁面大小的中間值，比如你的站點大部分腳本所產生的頁面大小為256k就可以把這個值設置為16 16k，或者4 64k 或者64 4k，但很顯然，後兩種並不是好的設置方法，因為如果產生的頁面只有32k，如果用4 64k它會分配1個64k的緩沖區去緩存，而如果使用64 4k它會分配8個4k的緩沖區去緩存，而如果使用16 16k則它會分配2個16k去緩存頁面，這樣看起來似乎更加合理。 
 
//+++++++++++++++++++++++++++++++++++++++++
client_max_body_size 100m; #允許客戶端請求的最大單文件字節數
client_body_buffer_size 2048k; #緩沖區代理緩沖用戶端請求的最大字節數，
fastcgi_buffer_size 1024k; 
fastcgi_buffers 6 256k; 
fastcgi_busy_buffers_size 1024k; 

fastcgi_buffer等於：fastcgi_buffer_size + the_number * is_size
fastcgi_buffers 256 4k; #設置buffer大小為：4k + 256 * 4k = 1028k
上面配置可以解決 an upstream response is buffered to a temporary file 或nginx+php-fpm慢問題

php502問題解決：recv() failed (104: Connection reset by peer) while reading response header from upstream

參考：https://blog.csdn.net/donglynn/article/details/76759548

nginx error: upstream prematurely closed connection while reading response header from upstream

參考：https://www.cnblogs.com/xinpureZhu/p/6142183.html

nginx access log 關閉

access_log off;

nginx error_log 日誌調整級別：

error_log  logs/error.log info|notice|warn|error;

nginx相關配置