http://www.jackxiang.com/index.php zh-cn http://www.jackxiang.com/post// jack <xdy108@126.com> Mon, 01 Dec 2014 06:50:22 +0000 http://www.jackxiang.com/post//
一、需求描述
一linode xen vps 1G RAM，40+sites，IO频繁，openfiles ulimit已65535
US时间访问量大增,nginx不定时502
二、解决办法
pages cache化,但这一台vps内存不够用，于是把闲置的几台服务器都装上memcached做缓存集群
再根据网络延迟设定权重
memcached server官方: http://memcached.org/
三、代码
访问memcached server需要php支持，可以选择memcached库和memcache库，注意2者名字的区别
详细对比：https://code.google.com/p/memcached/wiki/PHPClientComparison
我采用的是php memcache: http://php.net/manual/en/book.memcache.php 因为memcache不依赖libmemcached
//集群数组
$memserver = array(     array( 'host' => 'fast1.xxx.com' , 'port' => 13579 , 'weight' => 40 ),     array( 'host' => 'fast2.xxx.com' , 'port' => 13579 , 'weight' => 20 ),     array( 'host' => 'fast3.xxx.com' , 'port' => 13579 , 'weight' => 20 ),     array( 'host' => 'slow1.xxx.com' , 'port' => 24680 , 'weight' => 5 ),     array( 'host' => 'slow2.xxx.com' , 'port' => 24680 , 'weight' => 5 ),     array( 'host' => 'local.xxx.com' , 'port' => 11211 , 'weight' => 10 ) );
键值读、写、删就没什么说的了直接按文档sample写即可
考虑到以后的移植问题，记得首先检测环境是否支持memcache: class_exists(‘Memcache’)
下面是我的实现，因为特定需求，几个函数写的相对独立，memcache也没做全局实例化。
你可以根据自己需求把memcache在全局实例化，优化操作。
//---get content from memcache--- function getCache( $key ) {     Global $memserver;     $ret = false;     $key = md5( $key );     $mc  = new Memcache();     foreach ( $memserver as $s )         $mc->addServer( $s['host'], $s['port'], FALSE, $s['weight'] );     $ret = $mc->get( $key );     $mc->close();     unset( $mc );     return $ret; } //---set content from memcache--- function setCache( $key, $val ) {     Global $memserver;     $ret = false;     $key = md5( $key );     $mc  = new Memcache();     foreach ( $memserver as $s )         $mc->addServer( $s['host'], $s['port'], FALSE, $s['weight'] );     if( isset($val['cached']) )     {         $val['cached'] = 1;         $ret = $mc->set( $key , $val);     }     $mc->close();     unset( $mc );     return $ret; } //---delete content from memcache--- function delCache( $key ) {     Global $memserver;     $ret = false;     $key = md5( $key );     $mc  = new Memcache();     foreach ( $memserver as $s )         $mc->addServer( $s['host'], $s['port'], FALSE, $s['weight'] );     $ret = $mc->delete( $key , 0);     $mc->close();     unset( $mc );     return $ret; }

摘自：http://www.6zou.net/tech/php-memcached-group.html ]]> http://www.jackxiang.com/post//#blogcomment <user@domain.com> Thu, 01 Jan 1970 00:00:00 +0000 http://www.jackxiang.com/post//#blogcomment