1.mkdir magent  
2.cd magent/  
3.wget http://memagent.googlecode.com/files/magent-0.5.tar.gz  （笔记附件）
4.tar zxvf magent-0.5.tar.gz  
5. /sbin/ldconfig  
6.sed -i "s#LIBS = -levent#LIBS = -levent -lm#g" Makefile  
7.vi magent.c 添加
    #include <limits.h>
8. yum install libevent-devel libevent
9.make  
10.cp magent /usr/bin/magent  



2. magent  命令参数说明：
1.-h this message  
2.-u uid  
3.-g gid  
4.-p port, default is 11211. (0 to disable tcp support)  
5.-s ip:port, set memcached server ip and port  
6.-b ip:port, set backup memcached server ip and port  
7.-l ip, local bind ip address, default is 0.0.0.0 
8.-n number, set max connections, default is 4096 
9.-D do not go to background  
10.-k use ketama key allocation algorithm  
11.-f file, unix socket path to listen on. default is off  
12.-i number, max keep alive connections for one memcached server, default is 20 
13.-v verbose 


memcached -m 1 -u root -d -l 192.168.1.219 -p 11211
memcached -m 1 -u root -d -l 192.168.1.219 -p 11212
memcached -m 1 -u root -d -l 192.168.1.219 -p 11213

magent -u root -n 51200 -l 192.168.1.219 -p 12000 -s 192.168.1.219:11211 -s 192.168.1.219:11212 -b 192.168.1.219:11213
1、分别在11211、11212、11213端口启动3个Memcached进程，在12000端口开启magent代理程序；
2、11211、11212端口为主Memcached，11213端口为备份Memcached；
3、连接上12000的magent，set key1和set key2，根据哈希算法，key1被写入11212和11213端口的Memcached，key2被写入11212
和11213端口的Memcached；
4、当11211、11212端口的Memcached死掉，连接到12000端口的magent取数据，数据会从11213端口的Memcached取出。

测试流程：
# telnet 192.168.1.219 12000
Trying 1192.168.1.219...
Connected to 192.168.1。219.
Escape character is '^]'.
stats
memcached agent v0.4
matrix 1 -> 192.168.1.219:11211, pool size 0
matrix 2 -> 192.168.1.219:11212, pool size 0
END
set key1 0 0 5
reesu                 长度为5
STORED
set key2 0 0 6
reesu1             长度为5
STORED
quit
Connection closed by foreign host.


# telnet 192.168.1.219 11211
Trying 192.168.1.219...
Connected to 192.168.1.219.
Escape character is '^]'.
get key1
END
get key2
VALUE key2 0 6
reesun1
END
quit
Connection closed by foreign host.


# telnet 192.168.1.219 11212
Trying 192.168.1.219...
Connected to 1192.168.1.219.
Escape character is '^]'.
get key1
VALUE key1 0 5
reesun
END
get key2
END
quit
Connection closed by foreign host.


# telnet 192.168.1.219 11213
Trying 192.168.1.219...
Connected to 1192.168.1.219.
Escape character is '^]'.
get key1
VALUE key1 0 5(key长度)
hello
END
get key2
VALUE key2 0 6
reesun
END
quit
Connection closed by foreign host.