Memcache or Memcached installation for Drupal?

Question

I've been floating around the Google and everything's getting more confusing now. What i want to know is how to install Memcache or Memcached. Even which one to install, i'm still not sure. It is super confusing.

I'm on Redhat RHEL. Actually i have installed Memcached (with 'd`) on my Web Server. Then according to the articles, i enabled Php Extension, etc. Then what is supposed to happen? Totally no improvement in performance.

Then i feel thats not enough and i googled again. Some say to install on MySQL Server. So what about PHP Extension and Drupal Module which are supposed to be configured, if i install it on MySQL Server? I'm really not getting it.

So i have Drupal 7 and please let me know in simple way for which is the right one to follow :(

• Memcache or Memcached ? (Why this two so confusing?)
• Where to put at?
• Does it really need Drupal Module to work?

Please simply give me a straight dummy guide :(

Answer 1

"Memcache vs Memcached" - first one is a module (extension), second one is the daemon. See "Memcache Vs. Memcached" for full explanation

"Where to put at?" - you said you had it already installed on your server, it should be installed easily with some package manager e.g.:

pecl install memcache

"Does it really need Drupal Module to work?" - Yes, Drupal needs to know that you want to use memcache. The Drupal module will move cache, sessions and lock tables into memory (see https://drupal.org/project/memcache).

To make memcache module work, you need to put the following into settings.php (change you module path respectively):

# Memcache
$conf['cache_backends'][] = 'sites/all/modules/contrib/memcache/memcache.inc';
$conf['cache_default_class'] = 'MemCacheDrupal';

To see whether it works, go to "admin/config/system/memcache" (this is Drupal 7 path) and turn on "Show memcache statistics at the bottom of each page" - if everything works well, you should see something similar at the bottom of the page:

OPERATION   BIN             KEY                         HIT
get         cache_bootstrap cache_bootstrap-variables   1