consistencehash

https://github.com/replay/ngx_http_consistent_hash->downloadhttps://github.com/replay/ngx_http_consistent_hash/archive/master.zip[root soft]# wget https://github.com/replay/ngx_http_consistent_hash/archive/master.zip[root soft]# unzip master[root soft]# cd ngx_http_consistent_hash-master#readme[root ngx_http_consistent_hash-master]# /usr/local/nginx/sbin/nginx -Vnginx version: nginx/1.4.2built by gcc 4.4.7 20120313 (Red Hat 4.4.7-4) (GCC) configure arguments: --prefix=/usr/local/nginx[root soft]# cd nginx-1.4.2[root@localhost nginx-1.4.2]# lsauto     CHANGES.ru  configure  html     Makefile  objs    srcCHANGES  conf        contrib    LICENSE  man       README[root@localhost nginx-1.4.2]# ./configure --prefix=/usr/local/nginx --add-module=/root/soft/ngx_http_consistent_hash-master/[root@localhost nginx-1.4.2]# make &&make installcd nginx[root@localhost nginx]# cd sbin[root@localhost sbin]# ./nginx  upstream memserver {          server localhost:11211;        server localhost:11212;        server localhost:11213;    }         location / {            # root   html;           set $memcached_key $uri;           memcached_pass memserver;  // memserver为上面的memcache节点的名称           error_page 404 /writemem.php;           index  index.php index.html index.htm;        }    [root@localhost nginx]# /usr/local/bin/memcached -u nobody -vv    [root@localhost nginx]# /usr/local/bin/memcached -u nobody -vv -p 11212    [root@localhost nginx]# /usr/local/bin/memcached -u nobody -vv -p 11213    访问urlhttp://192.168.88.156/use5.html    <7 get /use5.html    >7 END   <7 connection closed.[root@localhost nginx]# vi conf/nginx.conf     upstream memserver {       consistent_hash $request_uri;#在一台上访问        server localhost:11211;        server localhost:11212;        server localhost:11213;    }root@localhost nginx]# ./sbin/nginx -s reload添加多台服务器php也要添加和nginx一样多的服务器$mem=new memcache();$mem->addServer('localhost',11211);$mem->addServer('localhost',11212);$mem->addServer('localhost',11213);修改php.inivim /usr/local/fastphp/lib/php.inimemcache.hash_strategy=consistentpkill -9 php-fpm/usr/local/fastphp/sbin/php-fpm大量访问量优化整体思路1.减少请求， expires利用浏览器缓存减少查询2.合并css背景图片减少mysql查询3.利用cdn响应请求4.最终剩下的，不可避免的请求，--服务集群+负载均衡来支撑配置memcache集群    upstream memserver {  把用到的memcached节点,声明在一个组里        hash_key $request_uri;  // hash计算时的依据,以uri做依据来hash        server localhost:11211;        server localhost:11212;    }Location里        location / {            # root   html;           set $memcached_key $uri;           memcached_pass memserver;  // memserver为上面的memcache节点的名称           error_page 404 /writemem.php;           index  index.php index.html index.htm;        }在nginx中做集群与负载均衡,步骤都是一样的Upstream {}模块 把多台服务器加入到一个组然后 memcached_pass, fastcgi_pass, proxy_pass ==> upstream组默认的负载均衡的算法:是设置计数器,轮流请求N台服务器.可以安装第3方模式,来利用uri做hash等等.如http://wiki.nginx.org/NginxHttpUpstreamConsistentHash 这个模块就是用一致性hash来请求后端结节,并且其算法,与PHP中的memcache模块的一致性hash算法,兼容.安装该模块后:Nginx.conf中    upstream memserver {         consistent_hash $request_uri;        server localhost:11211;        server localhost:11212;    }在PHP.ini中,如下配置memcache.hash_strategy = consistent这样: nginx与PHP即可完成对memcached的集群与负载均衡算法.