If you use a managed host, there won’t be as much to do to optimize your WordPress site. If you self-host, there’s a lot that you need to do.
Caching and Scaling
If your site receives thousands of requests, WordPress will struggle to build each page dynamically for each reader. It’s best practice to use some caching solution – so that most pages are stored on disk or in memory and served directly to your readers when they request them.
I’ve written an extensive guide to using Varnish Cache with the W3 Total Cache plugin on Apache. I find that this is an extremely straightforward, robust solution to scaling. This site regularly receives traffic from popular sites such as Slashdot, BoingBoing and Salon, sometimes simultaneously – and my caching configuration almost always handles this smoothly.
Because caching works primarily with readers that are not logged into your WordPress site, it’s useful to use a cacheable comment system besides WordPress, something like Disqus. This ensures that a higher percentage of page requests are served from your cache.
Content Delivery Network (CDN)
Setting up custom subdomains on an alternate domain from your primary site can speed delivery of CDN content. For example, my CDN serves from a different domain entirely than jeffreifman.com so that cookie data is not carried along with each file request.
Other Ways to Improve Performance
I’ve written a summary of other optimization tools here:
- Use the SQL tuning script to ensure your MySQL configuration is optimized for WordPress.
- Use Google Page Speed to see how your site is performing and where you might be able to improve speeds.
- Run the New Relic APM for PHP to get detailed server monitoring
- Use WP Optimize to cleanse your database