The memcache extension must be loaded for using this backend

PHP has two Memcached libraries with confusing names :

• Memcache
• Memcached (notice the d)

Your code needs the first one. Just do a simple pecl uninstall memcached and then pecl install memcache, modify your php.ini to include the appropiate .so and it should work.

needs extension called php-memcached possible solutions: (notice that extension is different from library, there are libraries called memcache & memchached, and extension called php-memcached. in my case the last one was needed) (on linux)

• to install extension:
  sudo apt-get install php-memcached
  this will help you.

follow below if library is also needed.

• to install library itself: sudo apt-get install memcached
• there is also a library containing memcached: sudo apt-get install libmemcached-tools

to read more and configure it you may want to check here and here

I solve this issue is quite simple. This issue happen because you didn't install php memcached extension. Let 's install it by this command in Ubuntu

sudo apt-get install php-memcached

Or in other OS you can figure out yourself

for the PHP library that you have installed, it looks like the easiest solution would be to use a different backend - if your zend framework version allows it:

Zend_Cache_Backend_Libmemcached (http://doczf.mikaelkael.fr/1.11/en/zend.cache.backends.html)

i assume that return Zend_Cache::factory('Core', 'Memcached', $frontendOpts, $backendOpts); turns into return Zend_Cache::factory('Core', 'Libmemcached', $frontendOpts, $backendOpts);