存储+调优：存储-memcached

什么是memcached?

    高性能的分布式内存缓存服务器。通过缓存数据库的查询结果，减少数据库访问次数，以提高动态Web应用的速度、提高可扩展性。

在memcached中存什么？

尽快被保存

访问频率高

1.数据保存方式 chunk

2.数据有效期

3.数据过期慵懒检查

4.数据的存取 set get

5。通过应用程序访问memcache

数据存储方式

chunk

数据过期方式

• Lazy Expiration

memcached内部不会监视记录是否过期，而是在get时查看记录的时间戳，检查记录是否过期。这种技术被称为lazy（惰性）expiration。因此，memcached不会在过期监视上耗费CPU时间。

• LRU

memcached会优先使用已超时的记录的空间，但即使如此，也会发生追加新记录时空间不足的情况，此时就要使用名为 Least Recently Used（LRU）机制来分配空间。顾名思义，这是删除“最近最少使用”的记录的机制。因此，当memcached的内存空间不足时（无法从slab class 获取到新的空间时），就从最近未被使用的记录中搜索，并将其空间分配给新的记录。从缓存的实用角度来看，该模型十分理想。

[root@localhost tmp]# tar xf libevent-2.0.15-stable.tar.gz 

[root@localhost tmp]# cd libevent-2.0.15-stable

[root@localhost libevent-2.0.15-stable]# ./configure && make && make install

[root@localhost tmp]# tar xf memcached-1.4.5.tar.gz 

[root@localhost tmp]# cd memcached-1.4.5

[root@localhost memcached-1.4.5]# ./configure && make && make install

[root@localhost memcached-1.4.5]# ./memcached -h

[root@localhost memcached-1.4.5]# ./memcached -p 11211 -l 172.16.1.6 -u root -m 64 -c 10 -vvv -f 1.2 -n 60

slab class   1: chunk size        96 perslab   10922

slab class   2: chunk size       120 perslab    8738

slab class   3: chunk size       144 perslab    7281

slab class   4: chunk size       176 perslab    5957

slab class   5: chunk size       216 perslab    4854

slab class   6: chunk size       264 perslab    3971

slab class   7: chunk size       320 perslab    3276

slab class   8: chunk size       384 perslab    2730

slab class   9: chunk size       464 perslab    2259

slab class  10: chunk size       560 perslab    1872

slab class  11: chunk size       672 perslab    1560

slab class  12: chunk size       808 perslab    1297

slab class  13: chunk size       976 perslab    1074

slab class  14: chunk size      1176 perslab     891

slab class  15: chunk size      1416 perslab     740

slab class  16: chunk size      1704 perslab     615

slab class  17: chunk size      2048 perslab     512

slab class  18: chunk size      2464 perslab     425

slab class  19: chunk size      2960 perslab     354

slab class  20: chunk size      3552 perslab     295

slab class  21: chunk size      4264 perslab     245

slab class  22: chunk size      5120 perslab     204

slab class  23: chunk size      6144 perslab     170

slab class  24: chunk size      7376 perslab     142

slab class  25: chunk size      8856 perslab     118

slab class  26: chunk size     10632 perslab      98

slab class  27: chunk size     12760 perslab      82

slab class  28: chunk size     15312 perslab      68

slab class  29: chunk size     18376 perslab      57

slab class  30: chunk size     22056 perslab      47

slab class  31: chunk size     26472 perslab      39

slab class  32: chunk size     31768 perslab      33

slab class  33: chunk size     38128 perslab      27

slab class  34: chunk size     45760 perslab      22

slab class  35: chunk size     54912 perslab      19

slab class  36: chunk size     65896 perslab      15

slab class  37: chunk size     79080 perslab      13

slab class  38: chunk size     94896 perslab      11

slab class  39: chunk size    113880 perslab       9

slab class  40: chunk size    136656 perslab       7

slab class  41: chunk size    163992 perslab       6

slab class  42: chunk size    196792 perslab       5

slab class  43: chunk size    236152 perslab       4

slab class  44: chunk size    283384 perslab       3

slab class  45: chunk size    340064 perslab       3

slab class  46: chunk size    408080 perslab       2

slab class  47: chunk size    489696 perslab       2

slab class  48: chunk size    587640 perslab       1

slab class  49: chunk size    705168 perslab       1

slab class  50: chunk size    846208 perslab       1

slab class  51: chunk size   1048576 perslab       1

<26 server listening (auto-negotiate)

<27 send buffer was 110592, now 268435456

<27 server listening (udp)

<27 server listening (udp)

<27 server listening (udp)

<27 server listening (udp)

[root@node1 ~]# telnet 172.16.1.6 11211

Trying 172.16.1.6...

Connected to 172.16.1.6 (172.16.1.6).

Escape character is '^]'.

<27 server listening (udp)

<27 server listening (udp)

<27 server listening (udp)

<27 server listening (udp)

<28 new auto-negotiating client connection

[root@node1 ~]# telnet 172.16.1.6 11211

Trying 172.16.1.6...

Connected to 172.16.1.6 (172.16.1.6).

Escape character is '^]'.

set nothing 0 180 10   ----- 0:标识  180：过期时间 10：多少字节

1234567890

STORED

get nothing

VALUE nothing 0 10

1234567890

END

[root@node1 ~]# yum install httpd php

[root@node1 ~]# rpm -ivh php-pecl-memcache-2.1.2-1.el5.rf.i386.rpm 

[root@node1 ~]# cp test.php /var/www/html/

[root@node1 ~]# vim /var/www/html/test.php 

$memcache = new Memcache;

$memcache->connect('172.16.1.6',11211) or die ("Could not connect");

$version = $memcache->getVersion();

echo "Server's version: ".$version."
\n";

$tmp_object = new stdClass;

$tmp_object->str_attr = 'test';

$tmp_object->int_attr = 123;

$memcache->set('key', $tmp_object, false, 10) or die ("Failed to save data at the server");

echo "Store data in the cache (data will expire in 10 seconds)
\n";

$get_result = $memcache->get('key');

echo "Data from the cache:
\n";

var_dump($get_result);

?>

[root@node1 ~]# service httpd start

[root@localhost ~]# elinks --dump http://172.16.1.1/test.php

   Server's version: 1.4.5

   Store data in the cache (data will expire in 10 seconds)

   Data from the cache:

   object(stdClass)#3 (2) { ["str_attr"]=> string(4) "test" ["int_attr"]=>

   int(123) }

apache + tomcat + memcached

apache 作为分发器

tomcat 提供web服务

mc     保证session同步

ip  192.168.1.106

apache:

    

    yum install httpd httpd-devel gcc -y

    

ajp1.3:

    tar zxvf tomcat-connectors-1.2.32-src.tar.gz  -C /tmp

    cat /tmp/tomcat-connectors-1.2.32-src/BUILD.txt 

    cd native

     ./configure --with-apxs=/usr/sbin/apxs 

    make && make install

    cp  ../conf/httpd-jk.conf /etc/httpd/conf.d/jk.conf

    vim /etc/httpd/conf.d/jk.conf

    JkMount   /*.jsp     wlb            

    JkMount   /manager/*     wlb

    

    cp  ../conf/workers.properties /etc/httpd/conf

    vim /etc/httpd/conf/workers.properties

    worker.list=wlb,jkstatus

    worker.wlb.type=lb

    worker.wlb.balance_workers=tomcat1,tomcat2

    worker.tomcat1.type=ajp13

    worker.tomcat1.host=192.168.1.111

    worker.tomcat1.port=8009

    worker.tomcat1.lbfactor=1

    worker.tomcat2.type=ajp13

    worker.tomcat2.host=192.168.1.112

    worker.tomcat2.port=8009

    worker.tomcat2.lbfactor=1

    /etc/init.d/httpd  restart

ip  192.168.1.111 192.168.1.112

jdk:

    service httpd stop

    chmod +x jdk-6u27-linux-i586.bin 

    ./jdk-6u27-linux-i586.bin 

    mv jdk1.6.0_27/ /usr/local/jdk

    vim /etc/bashrc

        export JAVA_HOME=/usr/local/jdk

        export JAVA_BIN=/usr/local/jdk/bin/

        export PATH=$JAVA_HOME/bin:$PATH

        export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

        export JAVA_HOME JAVA_BIN PATH CLASSPATH

    source /etc/bashrc 

    java -version

    mv apache-tomcat-6.0.32 /usr/local/tomcat

tomcat:

    tar zxf apache-tomcat-6.0.32.tar.gz 

    mv apache-tomcat-6.0.32 /usr/local/tomcat

    cd /usr/local/tomcat/bin 

    ./startup.sh 

cat >/usr/local/tomcat/webapps/ROOT/index.jsp <

<%= request.getSession().getId() %>

Tomcat 1