How do I ensure my Apache website will load quickly under high amounts of traffic?
There are several options for ensuring that your website loads quickly and is highly available.
The first is plan-related. Websites with high traffic will typically require a Linode with access to higher levels of resources that are less sensitive to CPU steal and other issues that can occur as a side-effect from cloud hosting.
You'll also want to make sure that your website's configurations are tailored to the amount and type of traffic you expect. Apache has documentation on their website detailing high-performance configuration recommendations. You'll likely want to install FastCGI to reduce the load on system resources. You may want to consider utilizing SQLite instead of MySQL if your database will fit within its guidelines. And you probably won't want to have anything that isn't website-related running on your Linode.
For high availability configurations, we recommend working through the steps in our high availability concepts guide as well as this additional guide to high availability. Ensuring that your website is accessible even if a server is down is equally as important as speed.
Continued monitoring and adjustment of expectations is the most important step. You may find that your initial configuration is not enough to offset the load on your website, or your web server and database application may go off the rails and cause OOMing. Continual monitoring of your Linode and tweaking your configurations as needed (whether via plan resizing or internal configurations) is a necessary piece of the puzzle.