Techniques for writing a scalable website

Question

I am new in the website scalability realm. Can you suggest to me some the techniques for making a website scalable to a large number of users?

Answer 1

In order of importance:

1. If you run PHP, use an opcode cache like APC. (This is important enough to be built-in in the next generation of PHP.)

2. Use YSlow or Google Page Speed to identify bottlenecks. (This will reveal structural problems with your website that affect both client and server performance.)

3. Ensure that your web server sends a proper Expires header for static content (images, Javascript, CSS), such that the browser can cache it properly. (YSlow will warn you about this, too.)

4. Use an HTTP accelerator, such as Varnish. (This picture says it all – and they already had an HTTP accelerator in place.)