-d选项是启动一个守护进程,
-m是分配给Memcache使用的内存数量,单位是MB,我这里是100MB,
-u是运行Memcache的用户,我这里是root,
-l是监听的服务器IP地址,如果有多个地址的话,我这里指定了服务器的IP地址192.168.36.200,
-p是设置Memcache监听的端口,我这里设置了11211,最好是1024以上的端口,我们这里统一使用11211
-c选项是最大运行的并发连接数,默认是1024,我这里设置了256,按照你服务器的负载量来设定。
-P是设置保存Memcache的pid文件,我这里是保存在/tmp/memcached.pid,
2)、如果要结束Memcache进程,执行:
[iyunv@localhost]# kill cat /tmp/memcached.pid
6、 监测是否启动成功方式
我们可以使用telnet来对我们的memcache服务器进行访问
例如:telnet 192.168.36.199 11211 (访问的是192.168.36.199这个ip的11211端口)
连接上后,直接敲击stats命令看当前缓存服务器状态
7、 设定memcache的telnet访问限制
请限定telnet的访问,使之只能在中转机上访问
8、 memcache的常见概念
memcached会预先分配内存,memcached分配内存方式称之为allocator,首先,这里有3个概念:
1 slab
2 page
3 chunk
解释一下,一般来说一个memcahced进程会预先将自己划分为若干个slab,每个slab下又有若干个page,每个page下又有多个chunk,如果我们把这3个咚咚看作是object得话,这是两个一对多得关系。再一般来说,slab得数量是有限得,几个,十几个,或者几十个,这个跟进程配置得内存有关。而每个slab下得page默认情况是1m,也就是说如果一个slab占用100m得内存得话,那么默认情况下这个slab所拥有得page得个数就是100,而chunk就是我们得数据存放得最终地方。
9、 Memcache的常用命令
Memcache常见的命令都在协议文件上:安装文件的的doc目录下的protocol.txt文件中有详细说明
1)、查询状态命令:stats:
Name Type Meaning
----------------------------------
pid 32u Process id of this server process
uptime 32u Number of seconds this server has been running
time 32u current UNIX time according to the server
version string Version string of this server
pointer_size 32 Default size of pointers on the host OS
(generally 32 or 64)
rusage_user 32u:32u Accumulated user time for this process
(seconds:microseconds)
rusage_system 32u:32u Accumulated system time for this process
(seconds:microseconds)
curr_items 32u Current number of items stored by the server
total_items 32u Total number of items stored by this server
ever since it started
bytes 64u Current number of bytes used by this server
to store items
curr_connections 32u Number of open connections
total_connections 32u Total number of connections opened since
the server started running
connection_structures 32u Number of connection structures allocated
by the server
cmd_get 64u Cumulative number of retrieval requests
cmd_set 64u Cumulative number of storage requests
get_hits 64u Number of keys that have been requested and
found present
get_misses 64u Number of items that have been requested
and not found
evictions 64u Number of valid items removed from cache
to free memory for new items
bytes_read 64u Total number of bytes read by this server
from network
bytes_written 64u Total number of bytes sent by this server to
network
limit_maxbytes 32u Number of bytes this server is allowed to
use for storage.
threads 32u Number of worker threads requested.
(see doc/threads.txt)
2)、查询版本号 version
3)、退出命令 quit
4)、显示各个slab的信息,包括chunk的大小、数目、使用情况等:stats slabs5)、显示各个slab中item的数目和最老item的年龄(最后一次访问距离现在的秒数):stats items
6)、显示内存分配:stats malloc
7)、清空缓存数据(其实是将所有缓存数据标记为过期):flush_all
memcached状态查看: