Nginx并发访问优化

sdtf08

Nginx反向代理并发能力的强弱，直接影响到系统的稳定性。安装Nginx过程，默认配置并不涉及到过多的并发参数，作为产品运行，不得不考虑这些因素。Nginx作为产品运行，官方建议部署到Linux64位系统，基于该建议，本文中从系统线之上考虑Nginx的并发优化。
 
1、打开Linux系统epoll支持
         epoll支持，能够大大提高系统网络IO的并发数。
 
2、Linux文件句柄数限制
         Nginx代理过程，将业务服务器请求数据缓存到本地文件，再将文件数据转发给请求客户端。高并发的客户端请求，必然要求服务器文件句柄的并发打开限制。
         使用ulimit命令，查看linux系统文件句柄并发限制。
         $ ulimit -n
          1024
     linux系统默认设为1024，我们需要将该值设为65535。
         修改系统文件/etc/security/limits.conf，添加如下信息，并重新启动系统生效。
         *               soft    nofile            65535
         *               hard    nofile            65535
        $ vi /etc/security/limits.conf
参考：http://shiguanghui.iyunv.com/admin/blogs/2201284
     
3、Nginx配置文件中，添加文件限制及连接数信息
    worker_rlimit_nofile 65535;
    events {
        use epoll;
        worker_connections  65535;
    }
    Nginx并发数受限，通常引起502错误，完成上述操作，通常情况都能解决。
 
 
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简介配置及优化：
1 nginx.conf 配置文件:
user    www www;
worker_processes 4;

# [ debug | info | notice | warn | error | crit ]
error_log    /usr/local/webserver/nginx/logs/nginx_error.log    crit;
pid                /usr/local/webserver/nginx/nginx.pid;
#Specifies the value for maximum file descriptors that can be opened by this process.
worker_rlimit_nofile 51200;
events
{
         use epoll;
         worker_connections 51200;
}

http
{
         include             mime.types;
         default_type    application/octet-stream;
         source_charset GB2312;
         server_names_hash_bucket_size 256;
         client_header_buffer_size 256k;
         large_client_header_buffers 4 256k;

         #size limits
         client_max_body_size             50m;
         client_body_buffer_size        256k;
         client_header_timeout     3m;
         client_body_timeout 3m;
         send_timeout             3m;
#参数都有所调整.目的是解决代理过程中出现的一些502 499错误     
         sendfile on;
         tcp_nopush         on;
         keepalive_timeout 120; #参数加大,以解决做代理时502错误
         tcp_nodelay on;
        
         include                    vhosts/upstream.conf;
         include                    vhosts/bbs.linuxtone.conf; 

}



2 upstream.conf 配置文件(这也是做负载的配置方法)
upstream.conf
            upstream bbs.linuxtone.com {
                 server 192.168.1.4:8099;
             }



3 站点配置文件
bbs.linuxtone.conf
server
     {
            listen             80;
            server_name    bbs.linuxtone.conf;
            charset GB2312;
            index index.html index.htm;
            root    /date/wwwroot/linuxtone/;

                location ~ ^/NginxStatus/ {
                        stub_status on;
                        access_log off;
                 }

         location / {
             root    /date/wwwroot/linuxtone/;
             proxy_redirect off ;
             proxy_set_header Host $host;
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header REMOTE-HOST $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
             client_max_body_size 50m;
             client_body_buffer_size 256k;
             proxy_connect_timeout 30;
             proxy_send_timeout 30;
             proxy_read_timeout 60;
             proxy_buffer_size 256k;
             proxy_buffers 4 256k;
             proxy_busy_buffers_size 256k;
             proxy_temp_file_write_size 256k;
             proxy_next_upstream error timeout invalid_header http_500 http_503 http_404;
             proxy_max_temp_file_size 128m;
             proxy_pass    http://bbs.linuxtone.com;
            }



#参数都有所调整.目的是解决代理过程中出现的一些502 499错误    
#Add expires header for static content
     location ~* \.(jpg|jpeg|gif|png|swf)$ {
         if (-f $request_filename) {
             root /date/wwwroot/linuxtone/;
             expires            1d;
             break;
            }
     }

         log_format    access    '$remote_addr - $remote_user [$time_local] "$request" '
                                                 '$status $body_bytes_sent "$http_referer" '
                                                 '"$http_user_agent" $http_x_forwarded_for';
        access_log    /exp/nginxlogs/bbs.linuxtone_access.log    access;
    
}