How do you get memcached working? I'm trying to get our Craft CMS install to use a memcached cluster we created in AWS. I am able to telnet to the memcached server on port 11211 from the server that will be connecting to it. I did a tcpdump (packet trace) on the web server's interface and it did not try to connect to the caching server at all over a period of 12 hours.

I have the caching method in config/general.php set to use "memcache" and have the useMemcached set to true in config/memcache.php as well as the memcached server info all filled out correctly. 

Is there something I am missing? It should have at least attempted to connect at least once in that amount of time. I was wondering if my web server was missing some sort of php plugin. I found libphp5-memcached wasn't installed so I installed it, but still no connection out. 

The documentation on getting Craft CMS to work with a caching server don't appear to have much more than the config stuff, so not sure what we're missing.

Thanks for the help in advance!
If this memcache cluster is purely for craft caching you could consider using redis instead.

I've found both the old and newer memcache implementations in php to be flaky, but those are personal experiences without any scientific proofs backing them.