Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering. Memcached is simple yet powerful. Its simple design promotes quick deployment, ease of development, and solves many problems facing large data caches. from memcached.org

Install Memcache

step 1: apt-get install memcached

step 2: service apache2 restart

step 3: apt-get install memcache

step 4: service apache2 restart

step 5: apt-get install php5-memcached

step 6: service apache2 restart

step 7: apt-get install php5-memcache

step 8: service apache2 restart