（1）介绍：

Memcached 是一个高性能的分布式内存对象缓存系统，用于动态Web应用以减轻数据库负载。它通过在内存中缓存数据和对象来减少读取数据库的次数，从而提高动态、数据库驱动网站的速度。Memcached基于一个存储键/值对的hashmap。其守护进程（daemon ）是用C写的，但是客户端可以用任何语言来编写，并通过memcached协议与守护进程通信。

（2）特点：

memcached作为高速运行的分布式缓存服务器，具有以下的特点：

1、协议简单；
2、基于libevent的事件处理；
3、内置内存存储方式；
4、memcached不互相通信的分布式。

（3）存储方式：

为了提高性能，memcached中保存的数据都存储在memcached内置的内存存储空间中。由于数据仅存在于内存中，因此重启memcached、重启操作系统会导致全部数据消失。另外，内容容量达到指定值之后，就基于LRU(Least Recently Used)算法自动删除不使用的缓存。memcached本身是为缓存而设计的服务器，因此并没有过多考虑数据的永久性问题。

二、memcached数据库配置：

1、准备安装所需源码包

[ ~]# mkdir /mnt/tools
[ ~]# mount.cifs //192.168.100.100/tools /mnt/tools/   ##挂载
Password for //192.168.100.100/tools:  
[ ~]# cd /mnt/tools/memcached/
[ memcached]# ls
LAMP-php5.6                   magent-0.5.tar.gz   memcached-1.5.6.tar.gz
libevent-2.1.8-stable.tar.gz  memcache-2.2.7.tgz
[ memcached]# 
[ memcached]# tar xf libevent-2.1.8-stable.tar.gz -C /opt/   ##解压
[ memcached]# tar xf memcached-1.5.6.tar.gz -C /opt/   ##解压
[ memcached]# cd /opt/
[ opt]# ls
libevent-2.1.8-stable  memcached-1.5.6  rh
[ opt]#

2、编译安装memcached

[ opt]# yum install gcc gcc-c++ make -y   ##安装依赖环境包
.............//省略过程
[ libevent-2.1.8-stable]# ./configure --prefix=/usr/local/libevent   ##配置libevent
.............//省略过程
[ libevent-2.1.8-stable]# make && make install   ##编译安装libevent
.............//省略过程
[ libevent-2.1.8-stable]# cd ../memcached-1.5.6/
[ memcached-1.5.6]# ./configure \   ##配置memcached
> --prefix=/usr/local/memcached > --with-libevent=/usr/local/libevent/
.............//省略过程
[ memcached-1.5.6]# make && make install   ##编译安装memcached
.............//省略过程
[ memcached-1.5.6]# ln -s /usr/local/memcached/bin/* /usr/local/bin   ##便于系统识别
[ memcached-1.5.6]#

3、开启memcached

[ memcached-1.5.6]# memcached -d -m 32m -p 11211 -u root
##开启数据库服务，-d守护进程 ；-m缓存大小32M ；-p端口11211
[ memcached-1.5.6]#
[ memcached-1.5.6]# netstat -ntap | grep memcached   ##查看端口
tcp        0      0 0.0.0.0:11211           0.0.0.0:*               LISTEN      22448/memcached     
tcp6       0      0 :::11211                :::*                    LISTEN      22448/memcached     
[ memcached-1.5.6]# 
[ memcached-1.5.6]# systemctl stop firewalld.service    ##关闭防火墙
[ memcached-1.5.6]# setenforce 0   ##关闭增强型安全功能
[ memcached-1.5.6]#

4、memcached数据库基础操作

[ memcached-1.5.6]# yum install -y telnet   ##安装Telnet服务
.............//省略过程
[ memcached-1.5.6]# telnet 127.0.0.1 11211   ##连接memcached数据库
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is ‘^]‘.
add username 0 0 7
添加数据（两个0表示：不进行压缩和序列化标识，数据过期时间为永不过期；标识号是7就需要输入7位数。）
1234567   ##输入7位的值
STORED  ##添加成功
add users 0 0 7
123   ##输入错误的值

ERROR   ##添加失败
get username      
VALUE username 0 7
1234567
END
gets username     ##查询数据
VALUE username 0 7 1
1234567
END
set username 0 0 8     ##更新信息，若键名不存在，则自行添加
12345678
STORED
gets username        ##查询数据
VALUE username 0 8 3
12345678
END
replace school 0 0 2     ##更新信息，若键名不存在，则报错
un 
NOT_STORED
get shcool        ##查询数据
END
replace username 0 0 9     ##更新信息，若键名不存在，则报错
123456789
STORED
gets username        ##查询数据
VALUE username 0 9 4
123456789
END
set school 0 0 4     ##更新信息，若键名不存在，则自行添加
1234
STORED
gets school        ##查询数据
VALUE school 0 4 5
1234
END
cas school 0 0 7 5    ##修改键的存储位数
logging
STORED
gets school   
VALUE school 0 7 6
logging
END
cas school 0 0 8 2
loggings
EXISTS
append school 0 0 4   ##键值后追加数据
book
STORED
gets school
VALUE school 0 11 7
loggingbook
END
prepend school 0 0 2    ##键值前追加数据
un
STORED
gets school
VALUE school 0 13 8
unloggingbook
END
delete school    ##清除指定的键值数据，清除所有缓存数据为flush_all
DELETED
get school
END
quit     ##退出
Connection closed by foreign host.
[ memcached-1.5.6]# 

##查看命令：
stats                                ##显示状态信息
stats items                      ##返回所有键值对的统计信息
stats cachedump 1 0      ##返回指定存储空间的键值对 
stats slabs                      ##显示各个slab的信息
stats sizes                      ##输出所有item的大小和个数
stats reset                      ##清空统计数据

三、客户端配置（部署LAMP架构）

LAMP架构之前的博客写过，想看详细解释的可以，看一下。下面就不做解释了。
LNMP架构

1、部署LAMP架构

[ ~]# mkdir /mnt/tools
[ ~]# mount.cifs //192.168.100.100/tools /mnt/tools/
Password for //192.168.100.100/tools:  
[ ~]# cd /mnt/tools/memcached/
[ memcached]# ls
LAMP-php5.6  libevent-2.1.8-stable.tar.gz  magent-0.5.tar.gz  memcache-2.2.7.tgz  memcached-1.5.6.tar.gz
[ LAMP-php5.6]# ls
apr-1.6.2.tar.gz       httpd-2.4.29.tar.bz2  mysql-5.6.26.tar.gz
apr-util-1.6.0.tar.gz  LAMP-php5.6.txt       php-5.6.11.tar.bz2
[ LAMP-php5.6]# 

[ LAMP-php5.6]# tar xf apr-1.6.2.tar.gz -C /opt/
[ LAMP-php5.6]# tar xf apr-util-1.6.0.tar.gz -C /opt/
[ LAMP-php5.6]# tar xf httpd-2.4.29.tar.bz2 -C /opt/
[ LAMP-php5.6]# 
[ LAMP-php5.6]# cd /opt/
[ opt]# ls
apr-1.6.2  apr-util-1.6.0  httpd-2.4.29  rh
[ opt]# mv apr-1.6.2/ httpd-2.4.29/srclib/apr
[ opt]# mv apr-util-1.6.0/ httpd-2.4.29/srclib/apr-util
[ opt]# ls
httpd-2.4.29  rh
[ opt]# 
[ opt]# cd httpd-2.4.29/
[ httpd-2.4.29]# yum -y install > gcc > gcc-c++ > make > pcre-devel > expat-devel > perl > zlib-devel

[ httpd-2.4.29]# ./configure > --prefix=/usr/local/httpd > --enable-so > --enable-rewrite > --enable-charset-lite > --enable-cgi

[ httpd-2.4.29]# make && make install

[ httpd-2.4.29]# cp /usr/local/httpd/bin/apachectl /etc/init.d/httpd
[ httpd-2.4.29]# vim /etc/init.d/httpd 
# chkconfig: 35 85 21  //35级别自动运行  第85个启动 第21个关闭
# description: Apache is a World Wide Web server
[ httpd-2.4.29]# chkconfig --add httpd
[ httpd-2.4.29]# 
[ httpd-2.4.29]# vim /usr/local/httpd/conf/httpd.conf 
ServerName www.yun.com:80
Listen 192.168.52.132:80
#Listen 80
[ httpd-2.4.29]# ln -s /usr/local/httpd/conf/httpd.conf /etc/
[ httpd-2.4.29]# ln -s /usr/local/httpd/bin/* /usr/local/bin/
[ httpd-2.4.29]# apachectl -t
Syntax OK
[ httpd-2.4.29]# 
[ httpd-2.4.29]# service httpd start 
[ httpd-2.4.29]# netstat -ntap | grep 80
tcp        0      0 192.168.52.132:80       0.0.0.0:*               LISTEN      88064/httpd         
[ httpd-2.4.29]# 
[ httpd-2.4.29]# cd /mnt/tools/memcached/LAMP-php5.6/
[ LAMP-php5.6]# ls
apr-1.6.2.tar.gz       httpd-2.4.29.tar.bz2  mysql-5.6.26.tar.gz
apr-util-1.6.0.tar.gz  LAMP-php5.6.txt       php-5.6.11.tar.bz2
[ LAMP-php5.6]# tar xf mysql-5.6.26.tar.gz -C /opt/
[ LAMP-php5.6]# cd /opt/
[ opt]# ls
httpd-2.4.29  mysql-5.6.26  rh
[ opt]# cd mysql-5.6.26/
[ mysql-5.6.26]# yum install -y ncurses-devel autoconf cmake
[ mysql-5.6.26]# cmake  > -DCMAKE_INSTALL_PREFIX=/usr/local/mysql > -DDEFAULT_CHARSET=utf8 > -DDEFAULT_COLLATION=utf8_general_ci > -DEXTRA_CHARSETS=all > -DSYSCONFIDIR=/etc > -DMYSQL_DATADIR=/home/mysql/ > -DMYSQL_UNIX_ADDR=/home/mysql/mysql.sock

[ mysql-5.6.26]# make && make install

[ mysql-5.6.26]# cp support-files/my-default.cnf /etc/my.cnf
cp：是否覆盖"/etc/my.cnf"？ yes
[ mysql-5.6.26]# cp support-files/mysql.server /etc/init.d/mysqld
[ mysql-5.6.26]# chmod 755 /etc/init.d/mysqld       
[ mysql-5.6.26]# chkconfig --add /etc/init.d/mysqld
[ mysql-5.6.26]# chkconfig  mysqld --level 235 on
[ mysql-5.6.26]# echo "PATH=$PATH:/usr/local/mysql/bin" >> /etc/profile
[ mysql-5.6.26]# source /etc/profile
[ mysql-5.6.26]# useradd -s /sbin/nologin mysql
[ mysql-5.6.26]# chown -R mysql:mysql /usr/local/mysql/
[ mysql-5.6.26]# 
[ mysql-5.6.26]# /usr/local/mysql/scripts/mysql_install_db > --user=mysql > --ldata=/var/lib/mysql > --basedir=/usr/local/mysql > --datadir=/home/mysql

[ mysql-5.6.26]# ln -s /var/lib/mysql/mysql.sock  /home/mysql/mysql.sock
[ mysql-5.6.26]# vim /etc/init.d/mysqld 
basedir=/usr/local/mysql
datadir=/home/mysql
[ mysql-5.6.26]# service mysqld start 
Starting MySQL. SUCCESS! 
[ mysql-5.6.26]# netstat -ntap | grep 3306
tcp6       0      0 :::3306                 :::*                    LISTEN      103429/mysqld       
[ mysql-5.6.26]# 

[ mysql-5.6.26]# service mysqld start 
Starting MySQL. SUCCESS! 
[ mysql-5.6.26]# netstat -ntap | grep 3306
tcp6       0      0 :::3306                 :::*                    LISTEN      103429/mysqld       
[ mysql-5.6.26]# 
[ mysql-5.6.26]# mysqladmin -u root -p password "abc123"
Enter password: 
Warning: Using a password on the command line interface can be insecure.
[ mysql-5.6.26]# mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.26 Source distribution

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

mysql> \q
Bye
[ mysql-5.6.26]# 

[ mysql-5.6.26]# cd /mnt/tools/memcached/LAMP-php5.6/
[ LAMP-php5.6]# ls
apr-1.6.2.tar.gz       httpd-2.4.29.tar.bz2  mysql-5.6.26.tar.gz
apr-util-1.6.0.tar.gz  LAMP-php5.6.txt       php-5.6.11.tar.bz2
[ LAMP-php5.6]# tar xf php-5.6.11.tar.bz2 -C /opt/
[ LAMP-php5.6]# cd /opt/
[ opt]# ls
httpd-2.4.29  mysql-5.6.26  php-5.6.11  rh
[ opt]# cd php-5.6.11/
[ php-5.6.11]# yum -y install > gd > libpng > libpng-devel > pcre > pcre-devel > libxml2-devel > libjpeg-devel
[ php-5.6.11]# ./configure > --prefix=/usr/local/php5 > --with-gd > --with-zlib > --with-apxs2=/usr/local/httpd/bin/apxs > --with-mysql=/usr/local/mysql > --with-config-file-path=/usr/local/php5 > --enable-mbstring 
[ php-5.6.11]# make && make install

[ php-5.6.11]# cp php.ini-development /usr/local/php5/php.ini
[ php-5.6.11]# ln -s /usr/local/php5/bin/* /usr/local/bin/
[ php-5.6.11]# ln -s /usr/local/php5/sbin/* /usr/local/sbin/
[ php-5.6.11]# 
[ php-5.6.11]# vim /etc/httpd.conf 
    AddType application/x-httpd-php .php
    AddType application/x-httpd-php-source .phps
<IfModule dir_module>
    DirectoryIndex index.html index.php
</IfModule>

[ php-5.6.11]# vim /usr/local/httpd/htdocs/index.php
<?php
phpinfo();
?>
[ php-5.6.11]# service httpd stop 
[ php-5.6.11]# service httpd start 
[ php-5.6.11]# systemctl stop firewalld.service 
[ php-5.6.11]# setenforce 0
[ php-5.6.11]#

2、测试访问，LAMP架构搭建成功

3、修改index.php文件

[ php-5.6.11]# vim /usr/local/httpd/htdocs/index.php
<?php
$link=mysql_connect(‘192.168.52.132‘,‘skyuser‘,‘admin123‘);
if($link) echo "<h1>Success!!</h1>";
else echo "Fail!!";
mysql_close();
?>

4、测试数据库工作是否正常

[ php-5.6.11]# mysql -u root -pabc123   ##进入数据库
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.6.26 Source distribution

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

mysql> create database sky;    ##创建一个数据库为 sky
Query OK, 1 row affected (0.00 sec)

mysql> grant all on sky.* to ‘skyuser‘@‘%‘ identified by ‘admin123‘;     ##提权
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges;    ##刷新权限
Query OK, 0 rows affected (0.01 sec)

mysql>

5、再次访问网页，显示success表示成功

6、安装 Memcache 客户端

[ php-5.6.11]# cd /mnt/tools/memcached/
[ memcached]# ls
LAMP-php5.6  libevent-2.1.8-stable.tar.gz  magent-0.5.tar.gz  memcache-2.2.7.tgz  memcached-1.5.6.tar.gz
[ memcached]# tar xf memcache-2.2.7.tgz -C /opt/   ##解压
[ memcached]# cd /opt/
[ opt]# ls
httpd-2.4.29  memcache-2.2.7  mysql-5.6.26  package.xml  php-5.6.11  rh
[ opt]# 
[ opt]# cd memcache-2.2.7/
[ memcache-2.2.7]# /usr/local/php5/bin/phpize 
Configuring for:
PHP Api Version:         20131106
Zend Module Api No:      20131226
Zend Extension Api No:   220131226
[ memcache-2.2.7]# 

[ memcache-2.2.7]# ./configure \   ##配置
> --enable-memcache > --with-php-config=/usr/local/php5/bin/php-config 

[ memcache-2.2.7]# make && make install   ##编译安装

7、配置 PHP，添加 Memcached 组件

[ memcache-2.2.7]# vim /usr/local/php5/php.ini
extension_dir = "/usr/local/php5/lib/php/extensions/no-debug-zts-20131226/"
extension=memcache.so

8、修改index.php文件，再重启httpd服务

[ memcache-2.2.7]# vim /usr/local/httpd/htdocs/index.php 
<?php
$memcache = new Memcache();
$memcache->connect(‘192.168.52.149‘,11211);
$memcache->set(‘key‘,‘Memcache test Successfull!‘,0,60);
$result = $memcache->get(‘key‘);
unset($memcache);
echo $result;
?>
[ memcache-2.2.7]# service httpd stop
[ memcache-2.2.7]# service httpd start 
[ memcache-2.2.7]#

9、客户端检测服务端是否可以正常连接