centOS安装memcached
Memcache是一个高性能的分布式的内存对象缓存系统,通过在内存里维护一个统一的巨大的hash表,它能够用来存储各种格式的数据.简单的说就是将数据调用到内存中,然后从内存中读取,从而大大提高读取速度。
工作原理:
①客户端第一次访问应用程序时,会到数据库(RDBMS)中取出数据,返回给客户端;同时也将取出的数据保存到memcached中。
② 第二次访问时,因为数据已经缓存,不不用去数据库查询了,直接从memcached取。
那么memcached的快速和高效率是如何体现出来的呢?我们都清楚,RDBMS是文件型的数据库,最终还是以文件的形式保存在磁盘上。而 memcached则不一样,它是key:value关系型的数据库,是保存在内存中的。那么就不用我再做说明了,内存的读写速度要比磁盘的读写速度快得多,前者是后者的10的6次方倍。http://blog.rekfan.com/?p=172
③memcached是基于libevent的事件处理。libevent是个程序库,它将Linux的epoll、BSD类操作系统的 kqueue等事件处理功能封装成统一的接口。即使对服务器的连接数增加,也能发挥O(1)的性能。 memcached使用这个libevent库,因此能在Linux、BSD、Solaris等操作系统上发挥其高性能。关于事件处理这里就不再详细介绍,可以参考Dan Kegel的The C10K Problem。欲了解更更多关于libevent:http://monkey.org/~provos/libevent/
安装Memcached步骤:
1.编译安装Libevent
Java代码 收藏代码
1. cd ~
2. wget https://github.com/downloads/libevent/libevent/libevent-2.0.19-stable.tar.gz
3. tar -zxvf libevent-2.0.19-stable.tar.gz
4. cd libevent-2.0.19-stable
5. ./configure --prefix=/usr/local/libevent/
6. make
7. make install
8. ln -s /usr/local/libevent/lib/libevent-2.0.so.5 /lib64/libevent-2.0.so.5
cd ~
wget https://github.com/downloads/libevent/libevent/libevent-2.0.19-stable.tar.gz
tar -zxvf libevent-2.0.19-stable.tar.gz
cd libevent-2.0.19-stable
./configure --prefix=/usr/local/libevent/
make
make install
ln -s /usr/local/libevent/lib/libevent-2.0.so.5 /lib64/libevent-2.0.so.5
2.安装Memcache
Java代码 收藏代码
1. cd ~
2. wget http://memcached.googlecode.com/files/memcached-1.4.13.tar.gz
3. tar -zxvf memcached-1.4.13.tar.gz
4. cd memcached-1.4.13
5. ./configure --prefix=/usr/local/memcached --with-libevent=/usr/local/libevent/
6. make
7. make install
cd ~
wget http://memcached.googlecode.com/files/memcached-1.4.13.tar.gz
tar -zxvf memcached-1.4.13.tar.gz
cd memcached-1.4.13
./configure --prefix=/usr/local/memcached --with-libevent=/usr/local/libevent/
make
make install
3.编写memcached服务启停脚本
Java代码 收藏代码
1. # cd /etc/init.d
2. vi memcached
# cd /etc/init.d
vi memcached
脚本内容如下:
Java代码 收藏代码
1. #!/bin/sh
2. #
3. # Startup script for the server of memcached
4. #http://blog.rekfan.com/?p=172
5. # processname: memcached
6. # pidfile: /usr/local/memcached/memcached.pid
7. # logfile: /usr/local/memcached/memcached_log.txt
8. # memcached_home: /etc/memcached
9. # chkconfig: 35 21 79
10. # description: Start and stop memcached Service
11.
12. # Source function library
13. . /etc/rc.d/init.d/functions
14.
15. RETVAL=0
16.
17. prog="memcached"
18. basedir=/usr/local/memcached
19. cmd=${basedir}/bin/memcached
20. pidfile="$basedir/${prog}.pid"
21. #logfile="$basedir/memcached_log.txt"
22.
23. # 设置memcached启动参数
24. ipaddr="192.168.1.101" # 绑定侦听的IP地址
25. port="11211" # 服务端口
26. username="root" # 运行程序的用户身份
27. max_memory=64 # default: 64M | 最大使用内存
28. max_simul_conn=1024 # default: 1024 | 最大同时连接数
29. #maxcon=51200
30. #growth_factor=1.3 # default: 1.25 | 块大小增长因子
31. #thread_num=6 # default: 4
32. #verbose="-vv" # 查看详细启动信息
33. #bind_protocol=binary # ascii, binary, or auto (default)
34.
35. start() {
36. echo -n $"Starting service: $prog"
37. $cmd -d -m $max_memory -u $username -l $ipaddr -p $port -c $max_simul_conn -P $pidfile
38. RETVAL=$?
39. echo
40. [ $RETVAL -eq 0 ] && touch /var/lock/subsys/$prog
41. }
42.
43. stop() {
44. echo -n $"Stopping service: $prog "
45. run_user=`whoami`
46. pidlist=`ps -ef | grep $run_user | grep memcached | grep -v grep | awk '{print($2)}'`
47. for pid in $pidlist
48. do
49. # echo "pid=$pid"
50. kill -9 $pid
51. if [ $? -ne 0 ]; then
52. return 1
53. fi
54. done
55. RETVAL=$?
56. echo
57. [ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$prog
58. }
59.
60. # See how we were called.
61. case "$1" in
62. start)
63. start
64. ;;
65. stop)
66. stop
67. ;;
68. #reload)
69. # reload
70. # ;;
71. restart)
72. stop
73. start
74. ;;
75. #condrestart)
76. # if [ -f /var/lock/subsys/$prog ]; then
77. # stop
78. # start
79. # fi
80. # ;;
81. status)
82. status memcached
83. ;;
84. *)
85. echo "Usage: $0 {start|stop|restart|status}"
86. exit 1
87. esac
88. exit $RETVAL
#!/bin/sh
#
# Startup script for the server of memcached
#http://blog.rekfan.com/?p=172
# processname: memcached
# pidfile: /usr/local/memcached/memcached.pid
# logfile: /usr/local/memcached/memcached_log.txt
# memcached_home: /etc/memcached
# chkconfig: 35 21 79
# description: Start and stop memcached Service
# Source function library
. /etc/rc.d/init.d/functions
RETVAL=0
prog="memcached"
basedir=/usr/local/memcached
cmd=${basedir}/bin/memcached
pidfile="$basedir/${prog}.pid"
#logfile="$basedir/memcached_log.txt"
# 设置memcached启动参数
ipaddr="192.168.1.101" # 绑定侦听的IP地址
port="11211" # 服务端口
username="root" # 运行程序的用户身份
max_memory=64 # default: 64M | 最大使用内存
max_simul_conn=1024 # default: 1024 | 最大同时连接数
#maxcon=51200
#growth_factor=1.3 # default: 1.25 | 块大小增长因子
#thread_num=6 # default: 4
#verbose="-vv" # 查看详细启动信息
#bind_protocol=binary # ascii, binary, or auto (default)
start() {
echo -n $"Starting service: $prog"
$cmd -d -m $max_memory -u $username -l $ipaddr -p $port -c $max_simul_conn -P $pidfile
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && touch /var/lock/subsys/$prog
}
stop() {
echo -n $"Stopping service: $prog "
run_user=`whoami`
pidlist=`ps -ef | grep $run_user | grep memcached | grep -v grep | awk '{print($2)}'`
for pid in $pidlist
do
# echo "pid=$pid"
kill -9 $pid
if [ $? -ne 0 ]; then
return 1
fi
done
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$prog
}
# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
#reload)
# reload
# ;;
restart)
stop
start
;;
#condrestart)
# if [ -f /var/lock/subsys/$prog ]; then
# stop
# start
# fi
# ;;
status)
status memcached
;;
*)
echo "Usage: $0 {start|stop|restart|status}"
exit 1
esac
exit $RETVAL
4.设置脚本可被执行:
Java代码 收藏代码
1. # chmod +x memcached
2. # chkconfig --add memcached
3. # chkconfig --level 35 memcached on
# chmod +x memcached
# chkconfig --add memcached
# chkconfig --level 35 memcached on
5.设置防火墙
Java代码 收藏代码
1. vi /etc/sysconfig/iptables
vi /etc/sysconfig/iptables
将下面这行加入进去
Java代码 收藏代码
1. -A RH-Firewall-l-INPUT -p tcp -m tcp --dport 11211 -j ACCEPT
-A RH-Firewall-l-INPUT -p tcp -m tcp --dport 11211 -j ACCEPT
注:将memcached加入到防火墙允许访问规则中
Java代码 收藏代码
1. service iptables restart
service iptables restart
注:防火墙重启
6.启动memcached
Java代码 收藏代码
1. # service memcached start
# service memcached start
//启动的时候实际上是调用了下面的这个命令,以守护进程的方式来启动memcached
Java代码 收藏代码
1. /usr/local/memcached/bin/memcached -d -m 64 -u root -l 192.168.1.101
2. -p 11211 -c 1024 -P /usr/local/memcached/memcached.pid
/usr/local/memcached/bin/memcached -d -m 64 -u root -l 192.168.1.101
-p 11211 -c 1024 -P /usr/local/memcached/memcached.pid
7.查看memcached是否启动:
Java代码 收藏代码
1. # ps -ef | grep memcached
# ps -ef | grep memcached
8.memcached命令参数解释