I'm hosting a large (>10 million posts), active forum on a single 16GB Linode running PHP 5.6 with Zend Opcache. It's very quick, and I'm considering installing Memcached for additional scalability and performance. But... is it going to be worth the trouble of using Memcached in such an environment? From my understanding of how MySQL and Memcached work, most of the relevant tables which Memcached could help with will already be stored in memory, making its additional cache redundant. I've seen many of you around here running Memcached in a single server environment, though, so I'm wondering if I may be wrong about this. Any advice or suggestions are appreciated.