How to: Install MemCached on CentOS / Redhat using yum

Installing memcached on a server for use with W3Total cache can seem daunting if you haven’t done it before.  Once you’ve done it enough to work out a method and know the speed bumps you can come across,  you can

 

 

Use this command to determine the CentOS/RedHat version. You need this to know if you are working with version 4 5 or 6.

cat /etc/redhat-release

Use this command to determine if the OS is 64bit or 32bit (look for x64. If it is not there, 99% of the time you’re on 32 bit.)

uname -a

Retrieve the IUS Community repository installation files to allow an easy install of the memcache module from the IUS repo.

Browse the repo at http://dl.iuscommunity.org/pub/ius/stable/Redhat/ to make certain you have the right files for your server:

This example is for 64 bit Red Hat Enterprise Linux (RHEL) 5 and is current as of 2014-03-04:

cd /usr/src/
mkdir ius
cd ius
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1.0-11.ius.el5.noarch.rpm
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-5-4.noarch.rpm

This example is for 32 bit Red Hat Enterprise Linux (RHEL) 5 and is current as of 2014-03-04:

cd /usr/src/
mkdir ius
cd ius
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/i386/ius-release-1.0-11.ius.el5.noarch.rpm
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/i386/epel-release-5-4.noarch.rpm

This example is for 64 bit Red Hat Enterprise Linux (RHEL) 6 and is current as of 2014-03-04:

cd /usr/src/
mkdir ius
cd ius
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/6/x86_64/ius-release-1.0-11.ius.el6.noarch.rpm
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/6/x86_64/epel-release-6-5.noarch.rpm

This example is for 32 bit Red Hat Enterprise Linux (RHEL) 6 and is current as of 2014-03-04:

cd /usr/src/
mkdir ius
cd ius
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/6/i386/ius-release-1.0-11.ius.el6.noarch.rpm
wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/6/i386/epel-release-6-5.noarch.rpm

CENTOS 7 64 bit

cd /usr/src/
mkdir ius
cd ius

wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/7/x86_64/ius-release-1.0-13.ius.el7.noarch.rpm

wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/7/x86_64/yum-plugin-replace-0.2.7-1.ius.el7.noarch.rpm

wget http://dl.fedoraproject.org/pub/epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm

 

Install both of these files:

rpm -ivh *.rpm

Perform the install:

yum -y install memcached
service memcached start
chkconfig memcached on
pecl install memcache

Note: If you get a “Can’t compile c code” error, try making your tmp folder executible before running the pecl command:

mount -o,remount,rw,exec /var/tmp

Make sure you remount the tmp directory securely with noexec when you are done:

mount -o,remount,rw,noexec /var/tmp

 

Make sure this line has correctly been added to the php.ini file for your site:

extension=”memcache.so”

Sometimes the php.ini file has been overridden for a specific directory. Look for that, if phpinfo() tells you memcache is not active.  This picture shows a site with the default php.ini overridden by a local copy. It required the extension line to be manually added to the overriding ini file.

phpinfo() output