memcached安装

1、安装扩展源

yum install -y epel-release

[root@localhost ~]# wget www.lishiming.net/data/attachment/forum/epel-release-5-4_32.noarch.rpm

[root@localhost ~]# rpm -ivh epel-release-5-4_32.noarch.rpm 

[root@localhost ~]# rpm -qa epel-release
epel-release-5-4.noarch

表明已经安装成功。

2、安装

[root@localhost ~]# yum install -y libevent memcached libmemcached

3、启动memcached

     [root@localhost ~]# /etc/init.d/memcached start

     Starting memcached:                                        [  OK  ]

     [root@localhost ~]#  

4、查看memcached的监听端口  （默认是11121）

[root@localhost ~]# netstat -lnp|grep memcached
tcp          0      0 0.0.0.0:11211               0.0.0.0:*                   LISTEN      3322/memcached      
tcp          0      0 :::11211                    :::*                        LISTEN      3322/memcached      
udp        0      0 0.0.0.0:11211               0.0.0.0:*                               3322/memcached      
udp        0      0 :::11211                    :::*                                    3322/memcached  

5、查看其进程

[root@localhost ~]# ps aux|grep memcached 
496       3322  0.0  0.0  58188   888 ?        Ssl  00:21   0:00 memcached -d -p 11211 -u memcached -m 64 -c 1024 -P /var/run/memcached/memcached.pid
root      3347  0.0  0.0   4420   760 pts/2    S+   00:24   0:00 grep memcached

6、查看其启动脚本

[root@localhost ~]# cat /etc/init.d/memcached

7、配置文件

[root@localhost ~]# cat /etc/sysconfig/memcached
PORT="11211"            #端口号
USER="memcached" #用户名
MAXCONN="1024"   #最大连接数 单位是M
CACHESIZE="64"        #内存大小
OPTIONS=""

8、查看memcached运行状态

  a、memcached-tool 127.0.0.0.1:11211 stats

  b、或者echo stats |nc 127.0.0.1 11211 需要安装nc工具（yum install -y nc）

  c、若是安装libmemcached 后，可以使用命令 memstat --servers=127.0.0.1:11211查看memcached的服务状态

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[root@localhost ~]# memcached-tool 127.0.0.1:11211 stats
#127.0.0.1:11211   Field       Value
         accepting_conns           1
               auth_cmds           0
             auth_errors           0
                   bytes           0
              bytes_read           7
           bytes_written           0
              cas_badval           0
                cas_hits           0
              cas_misses           0
               cmd_flush           0
                 cmd_get           0
                 cmd_set           0
             conn_yields           0
   connection_structures           6
        curr_connections           5
              curr_items           0
               decr_hits           0
             decr_misses           0
             delete_hits           0
           delete_misses           0
               evictions           0
                get_hits           0
              get_misses           0
               incr_hits           0
             incr_misses           0
          limit_maxbytes   134217728
     listen_disabled_num           0
                     pid        3460
            pointer_size          32
               reclaimed           0
           rusage_system    0.008998
             rusage_user    0.000000
                 threads           4
                    time  1448354429
       total_connections           6
             total_items           0
                  uptime         194
                 version       1.4.5

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[root@localhost ~]# echo stats |nc 127.0.0.1 11211
STAT pid 3460
STAT uptime 297
STAT time 1448354532
STAT version 1.4.5
STAT pointer_size 32
STAT rusage_user 0.000000
STAT rusage_system 0.013997
STAT curr_connections 5
STAT total_connections 7
STAT connection_structures 6
STAT cmd_get 0
STAT cmd_set 0
STAT cmd_flush 0
STAT get_hits 0
STAT get_misses 0
STAT delete_misses 0
STAT delete_hits 0
STAT incr_misses 0
STAT incr_hits 0
STAT decr_misses 0
STAT decr_hits 0
STAT cas_misses 0
STAT cas_hits 0
STAT cas_badval 0
STAT auth_cmds 0
STAT auth_errors 0
STAT bytes_read 13
STAT bytes_written 784
STAT limit_maxbytes 134217728
STAT accepting_conns 1
STAT listen_disabled_num 0
STAT threads 4
STAT conn_yields 0
STAT bytes 0
STAT curr_items 0
STAT total_items 0
STAT evictions 0
STAT reclaimed 0
END

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[root@localhost ~]# memstat --servers=127.0.0.1:11211
Listing 1 Server

Server: 127.0.0.1 (11211)
     pid: 3460
     uptime: 394
     time: 1448354629
     version: 1.4.5
     pointer_size: 32
     rusage_user: 0.0
     rusage_system: 0.17997
     curr_items: 0
     total_items: 0
     bytes: 0
     curr_connections: 5
     total_connections: 8
     connection_structures: 6
     cmd_get: 0
     cmd_set: 0
     get_hits: 0
     get_misses: 0
     evictions: 0
     bytes_read: 0
     bytes_written: 0
     limit_maxbytes: 134217728
     threads: 4

知识点

1、相关的参数 在/etc/init.d/memcached 和/etc/sysconfig/memcached中定义

2、Memcached 启动参数

  -d  选项是启动一个守护进程

  -m 是分配给memcache使用内存数量，单位是MB，这里的是128MB

  -u  是运行Memcache的用户，如果当前为root的话，需要使用此参数指定用户。

  -l   是监听的服务器的IP地址

  -p  是设置memcache监听的端口号，默认是11211

  -c   选项是最大运行的并发连接数，默认是1024

  -P  是设置保存Memcache的pid文件，

3、设置监听的端口号

[root@localhost ~]# vim /etc/sysconfig/memcached 

PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="128"
OPTIONS="-l 127.0.0.1" #设置本地为监听

重启memcached，然后查看，

[root@localhost ~]# vim /etc/sysconfig/memcached 
[root@localhost ~]# service memcached restart
Stopping memcached:                                        [  OK  ]
Starting memcached:                                        [  OK  ]
[root@localhost ~]# ps aux|grep memcached 
496       3460  0.0  0.0  58188   820 ?        Ssl  00:37   0:00 memcached -d -p 11211 -u memcached -m 128 -c 1024 -P /var/run/memcached/memcached.pid -l 127.0.0.1
root      3472  0.0  0.0   4420   756 pts/2    R+   00:37   0:00 grep memcached

[root@localhost ~]# netstat -lnp|grep memcached
tcp        0      0 127.0.0.1:11211             0.0.0.0:*                   LISTEN      3460/memcached       #监听的端口号
udp        0      0 127.0.0.1:11211             0.0.0.0:*                               3460/memcached