Install Memcached on CentOS/RHEL 5/6/7

Memcached is a distributed, high-performance, in-memory caching system that is primarily used to speed up sites that make heavy use of databases. Memcached is likewise used to cache whole database tables and queries to enhance execution of database. Memcached keeps running in memory and is in this way entirely quick, since it doesn’t have to write data to disk.

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The easiest way to introduce Memcached is through a package manager, for example, yum. However, Memcached is not accessible from the default collection of packages, so the first thing we have to do is add a new repository server so we can install Memcached through yum.

Step #1 Install Repository

The fastest and easiest way to install and enable EPEL repository using YUM.

CentOS/RHEL 7 64bit:
# rpm -Uvh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
CentOS/RHEL 6 64bit:
# rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
CentOS/RHEL 6 32 Bit:
# rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
CentOS/RHEL 5 64bit:
# rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
CentOS/RHEL 5 32 Bit:
# rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm

Step #2 Install Memcached

Now as simple as running just following command to install Memcached:

# yum install memcached -y

Step #3 Configure Memcached

After installing Memcached, Open the configuration file of Memcached.

# vim /etc/sysconfig/memcached

PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="64"
OPTIONS=""

Memcached isn’t protected with a password or username so anyone can access it through port 11211. So we are going to allow only for our server to access it. Do changes as below:

PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="64"
OPTIONS="-l 127.0.0.1"

Note: Detail of above parameters

After the changes restart Memcached.

CentOS/RHEL 7:
# systemctl restart memcached
CentOS/RHEL 6/5:
# /etc/init.d/memcached restart

Step #4 Start on Boot

Now start Memcached on boot, so that If server reboot then Memcached service start automatically.

CentOS/RHEL 7:
# systemctl enable memcached
CentOS/RHEL 6/5:
# chkconfig memcached on

Step #5 Verify Memcached

Verify memcached using netstat command:

# netstat -tulpn | grep 11211

Check the stats of the server using memcached-tool.

# echo "stats settings" | nc localhost 11211

Step #6 Install Memcached PHP extension

Now we have installed Memcached server on our system. In any case, to use Memcached service using php scripts we have to install Memcache php augmentation.

# yum install php-pecl-memcache

Install Memcached Perl Library

If require install perl library for Memcached.

# yum install perl-Cache-Memcached

Install Memcached Python Library

If require install python library for Memcached.

# yum install python-memcached

After installing require packages restart the Apache service to reflect changes.

CentOS/RHEL 7:
# systemctl restart httpd
CentOS/RHEL 6/5:
# /etc/init.d/httpd restart

Cache MySQL Queries with Memcached

It isn’t a simple assignment for everything, you need to use API’s to modify your PHP codes to empower MySQL caching. You can discover the samples codes at Memcache with MySQL and PHP.

Enjoy it!