Hands down, the nginx caching proxy. Some requests are very expensive, RSS feeds, for instance. A caching proxy (or perhaps WP Super Cache) is a necessity. A default, uncached WordPress deploy is not going to get you far.

You definitely want a physical machine to maximize MySQL IO. You should tune it properly for the large amount of RAM you’ve surely installed in it.

Your WordPress app server needs multiple cores to maximize concurrency.

Be sure to use a PHP opcode cache – APC has been nothing but unicorns and rainbows for us.

We could probably handle double the traffic with our current hardware, and nginx can load balance for us if/when we need to use multiple WordPress application servers. Our performance problems have not been related to our MySQL server so far.

Posted in: Blog Admin FAQs