OpenX - How to enable memcached

This tutorial shows you how to enable "memcached" plugin in OpenX. "memcached" is very useful to increase performance.
OS: Ubuntu 12.04.3 LTS

First of all, you should have memcached server installed:

# dpkg -l | grep memcache

ii  libmemcached6                     0.44-1.1build1                    A C and C++ client library to the memcached server
ii  memcached                         1.4.13-0ubuntu2                   A high-performance memory object caching system
ii  php5-memcached                    1.0.2-2                           memcached extension module for PHP5, uses libmemcached

If you don't have memcached, install it:

# apt-get install memcached
# apt-get install php5-memcached
# /etc/init.d/memcached start
# ps -ef | grep memcach
memcache   915     1  0  2013 ?        00:14:12 /usr/bin/memcached -m 64 -p 11211 -u memcache -l 127.0.0.1

In OpenX admin page, "http://server.com/admin/", change URL to "http://server.com/admin/plugin-settings.php?group=oxMemcached" (By default the oxMemcached is not listed). Set configuration parameters for your memcached server.

Now go back to "Administrator account" -> "Configuration". Set ‘Banner Delivery Cache Settings“ to Memcached.

If you see this warning " It is possible to edit all settings because the configuration file is not locked, but this could lead to security issues. If you want to secure your system, you need to lock the configuration file for this installation.",

To UnLock Configuration File :

    chmod 666 openx/var/ads.hackersgarage.com.conf.php

To Lock Configuration file back :

    chmod 644 openx/var/ads.hackersgarage.com.conf.php

It is recommended to lock it back when you are finished with your web based configuration.