互联网上讲述nginx高并发配置的比较多，主要是nginx+php。本博讲述nginx java web应用配置，实现高并发。配置关键点，见下文

配置cpu核数

worker_processes  10;

worker_rlimit_nofile 102400;

配置epoll网络模型 worker_connections线程数，开到上万

events {
    use epoll;
    worker_connections  10240;
}

图片资源cache

http{
	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;
	#控制缓冲区溢出攻击
	client_body_buffer_size  1K;
	client_header_buffer_size 1k;
	client_max_body_size 1k;
	large_client_header_buffers 2 1k;
	##cache##
	proxy_connect_timeout 5;
	proxy_read_timeout 60;
	proxy_send_timeout 5;
	proxy_buffer_size 16k;
	proxy_buffers 4 64k;
	gzip_proxied any;
	proxy_busy_buffers_size 128k;
	proxy_temp_file_write_size 128k;
	proxy_temp_path /home/temp_dir;
	proxy_cache_path /home/cache levels=1:2 keys_zone=<span style="color:#ff0000;"><strong>cache_one</strong></span>:200m inactive=1d max_size=1g;

        #gzip#
	gzip    on;
	gzip_vary on;
	gzip_min_length   1k;
	gzip_buffers   4 8k;
	gzip_comp_level 4;
	gzip_http_version  1.0;
        gzip_types   text/plain  text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;
	gzip_disable "MSIE [1-6]\.";
}

#图片前端缓存

location ~ .*\.(jsp|do|action)?$
		{
			# $server_port 可以不要，只有nginx的端口是非80情况下有效
			proxy_set_header Host $host:$server_port;
			proxy_set_header        X-Real-IP $remote_addr;
			proxy_set_header X-Forwarded-For $remote_addr;
			proxy_pass http://tc;
		}
		location ~ .*\.(gif|jpg|png|htm|html|css|flv|ico|swf) {
			proxy_pass http://tc;
			proxy_redirect off;
			proxy_cache_key $host$uri$is_args$args;
			proxy_set_header Host $host;
			proxy_cache <span style="color:#ff0000;"><strong>cache_one</strong></span>;
			proxy_cache_valid 200 302 1h;
			proxy_cache_valid 301 1d;
			proxy_cache_valid any 1m;
			expires 30d;
		}

		location ~ .*\.(js)?$
		{
			expires   1h;
		} 

nginx负载均衡

负载均衡策略较多，这里主要使用三种 ：

ip_hash：Ip粘滞，对于web端没有很成熟的会话复制方案，使用Ip粘滞。用户登录后，会话保持在一台PC上。

least_conn：最小连接数

轮询 ：默认。按请求时间顺序，分配给后端服务器

其它策略

fair：第三方，未研究。按后端服务器的响应时间来分配请求，响应时间短的优先分配

url_hash:第三方，未研究。

linux操作系统

vi /etc/sysctl.conf增加或者修改参数

net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.nf_conntrack_max = 655360
net.netfilter.nf_conntrack_tcp_timeout_established = 1200

<p><span style="background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">kernel.shmall = 4294967296</span></p><p><span style="font-family: Arial, Helvetica, sans-serif; background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">net.ipv4.tcp_max_tw_buckets =</span><span style="font-family: Arial, Helvetica, sans-serif; background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">6</span><span style="font-family: Arial, Helvetica, sans-serif; background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">000</span></p>

vi /etc/security/limits.conf

* soft nofile 1024000
* soft nproc 1024000
* hard nofile 1024000
* hard nproc 1024000