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一、需求描述 一linode xen vps 1G RAM,40sites,IO频繁,openfilesulimit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 memcache
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
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//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 )
);
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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。
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//---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 ;
}
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