How to Install Memcached on Fedora 16/15, CentOS/Red Hat (RHEL) 6.2/5.7

Memcached is a high-performance, distributed memory object caching system, generic in nature, but originally intended for use in speeding up dynamic web applications by alleviating database load. Memcached is a very useful also in other cases, than only dynamic web applications.

This guide explains howto install Memcached 1.4.4/1.4.5/1.4.7 stable version of distributed memory object caching system on Fedora 16/15/14/13/12 and CentOS 6.2/6.1/6/5.7, Red Hat (RHEL) 6.2/6.1/6/5.7. Fedora 16/15/14/13/12, CentOS 6 and Red Hat (RHEL) 6 has Memcached 1.4.5 as default so extra repositories is not needed.

Install Memcached 1.4.4/1.4.5/1.4.7 on Fedora 16/15/14/13/12, CentOS/Red Hat (RHEL) 6.2/6.1/6/5.7

Install Remi repository (not needed on Fedora 16, Fedora 15, Fedora 14, Fedora 13, Fedora 12 and RHEL 6):

## Remi Dependency on CentOS and Red Hat (RHEL)
rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm
 
rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-5.rpm

Install Memcached package

Fedora 16/15/14/13/12, CentOS/Red Hat (RHEL) 6.2/6.1/6

yum install memcached

CentOS/Red Hat (RHEL) 5.7

yum --enablerepo=remi install memcached

Configure memcached

Most important value to configure is CACHESIZE, which is cache size on Megabytes. Example Following configuration use 512 Mb memory for Memcached

nano -w /etc/sysconfig/memcached
PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="512"
OPTIONS=""

 

Start Memcached

# Set Memcached to start automatically on boot
chkconfig memcached on
# Start Memcached
/etc/init.d/memcached start
## OR ##
service memcached start

 

Check that Memcached is Running and Working

echo stats | nc localhost 11211
STAT pid 7599
STAT uptime 10
STAT time 1265288542
STAT version 1.4.4
STAT pointer_size 32
STAT rusage_user 0.003999
STAT rusage_system 0.052991
STAT curr_connections 10
STAT total_connections 11
STAT connection_structures 11
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 6
STAT bytes_written 0
STAT limit_maxbytes 536870912
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
END
 
# Try to get some value
echo get some_value | nc localhost 11211
END
 
# Not found, but check the stats again
echo stats | nc localhost 11211
STAT pid 7599
STAT uptime 10
STAT time 1265288542
STAT version 1.4.4
[...]
STAT cmd_get 1
STAT cmd_set 0
STAT cmd_flush 0
STAT get_hits 0
STAT get_misses 1
STAT delete_misses 0
[...]
STAT evictions 0
END

Everything working nice. Then it’s time to test memcache example with some web application.

Open Memcached Port (11211) on Iptables Firewall (If the Memcached will also be used other local servers)

 

Edit /etc/sysconfig/iptables file:

nano -w /etc/sysconfig/iptables

 

Add following line before COMMIT:

-A INPUT -m state --state NEW -m tcp -p tcp --dport 11211 -j ACCEPT

 

Restart Iptables Firewall:

service iptables restart
## OR ##
/etc/init.d/iptables restart

 

Test remote connection:

echo stats | nc memcache_host_name_or_ip 11211

 

Install Memcache and/or Memcached PHP Module on Fedora, CentOS and Red Hat (RHEL)

More information about Memcache Module.
More information about Memcached Module.

Install Memcache Module and PHP

yum install php php-pecl-memcache

 

Install Memcached Module and PHP

yum install php php-pecl-memcached

 

Restart Web server

/etc/init.d/httpd restart
## OR ##
service httpd restart

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