After installing memcached daemon, we have to install memcache PHP extension.

yum install php-pecl-memcache

or

apt-get install php5-memcache

If above is not an option try below method.

pecl install memcache

After successful installation add memcache.so extension to your php.ini file.

vim /etc/php.ini

Add this line:

extension=memcache.so

Restart web server

service httpd restart

Test out our installation.

<?php
$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ('Can\'t connect!');
$version = $memcache->getVersion();
echo 'Server version: '.$version;

You should see your server’s version number. If you see a blank page make sure that memcached daemon is working. If you’re getting "Can’t connect!" message despite running daemon try changing 'localhost' to '127.0.0.1'.

Install dependancy

Before we install memcached we need a dependency library libevent. Check for latest stable version at https://monkey.org/~provos/libevent/

cd /usr/local/src
wget http://monkey.org/~provos/libevent-1.4.13-stable.tar.gz
tar -xzvf libevent-1.4.13-stable.tar.gz
cd libevent-1.4.13-stable
./configure --prefix=/usr/local
make
make install
cd ..

Install memcached

Check for latest stable version at https://memcached.org/

wget http://memcached.googlecode.com/files/memcached-1.4.4.tar.gz
tar -xzvf memcached-1.4.4.tar.gz
cd memcached-1.4.4
LDFLAGS='-Wl,--rpath /usr/local/lib'
./configure --prefix=/usr/local
make
make install

More information about LDFLAGS https://en.wikipedia.org/wiki/Linker

Run memcached as a daemon

Basic options: d = daemon, m = memory, u = user, l = IP to listen to, p = port

memcached -u root -d

or

memcached -u root -d -m 512 -l 127.0.0.1 -p 11211

To stop daemon type

pkill memcached

Now we’re off to installing php extension memcache.

Problem

Sometimes after running yum update or yum install something you’re getting missing dependency error messages. Like this:

--> Missing Dependency: /usr/lib64/python2.4 is needed by package gamin-python-0.1.7-8.el5.x86_64 (installed)
--> Missing Dependency: /usr/lib64/python2.4 is needed by package libxml2-python-2.6.26-2.1.2.8.x86_64 (installed)

This means that some other package needs to be installed in order to install the one you want. If you have all dependencies installed and you’re still getting those messages all you need to do is clean yum’s cache.

Solution

Run one of these (taken from yum manual):

The following are the ways which you can invoke yum in clean mode. Note that "all files" in the commands below means "all files in currently enabled repositories". If you want to also clean any (temporarily) disabled repositories you need to use –enablerepo='*' option.

yum clean packages

Eliminate any cached packages from the system. Note that packages are not automatically deleted after they are downloaded.

yum clean headers

Eliminate all of the header files which yum uses for dependency resolution.

yum clean metadata

Eliminate all of the files which yum uses to determine the remote availability of packages. Using this option will force yum to download all the metadata the next time it is run.

yum clean dbcache

Eliminate the sqlite cache used for faster access to metadata. Using this option will force yum to recreate cache next time it is run.

yum clean all

Runs yum clean packages and yum clean headers, yum clean metadata and yum clean dbcache as above.

Now run again your yum update or any other yum install command and it should be fine.