With their decade of experience and expert domain knowledge, Automattic have an inherent advantage in delivering these sites, but it’s also within the reach of any other company with access to major in-house technical resources who are prepared to obsessively tune every layer of the stack.
WordPress is, at the end of the day, merely one link in a chain when it comes to the architecture of a high-performance, high-traffic sites, and in many ways it’s one of the less relevant ones when it comes to dealing with things at scale.
If you’re looking for an accessible account of exactly how much behind the scenes blood, sweat and tears can be involved in getting a site tooled up for web-scale traffic, have a read of Paul Ford’s excellent recent piece on how PAPER magazine’s engineers scaled their backend for Kim Kardashian to handle over 30 million pageviews in just a few days.
The editorial interface in that instance was Movable Type rather than WordPress, but if you read the article you’ll see that the choice of CMS is way down the list of concerns for delivering this type of traffic.
If you’re expecting the world to show up at your virtual door, you’ll need an expert team administering a highly optimized setup in terms of some or all of the following:
- Underlying server hardware and RAM
- Caching and load balancing
- Content Delivery Network
- Web server tuning
- Multiple, well-tuned databases
Smashing Magazine had a great roundup a few years ago of how large-scale WordPress sites have dealt with many of the items on that list if you want to start diving into the technical specifics of how to implement.
And, if you’re trying to get a handle on current best practices in the space, there’s no better starting point than WP Engine’s Scaling WordPress for High Traffic white paper.
Mark Seifert of AvatarPress made an interesting related point in regard to much of the above on another recent WordPress scaling thread on Quora:
“I reached a point where I realized it was far more cost-effective to invest in more hardware than to spend huge amounts of time squeezing small performance gains out of a theme or plugin’s WP queries at the subatomic level.”
To sum up, assuming you’re working with a well-optimized WordPress setup to begin with, the big gains in performance at scale are likely to be elsewhere in the stack these days.