High traffic web sites

Question

What makes a site good for high traffic? Does it have more to do with the hardware/infrastructure, or with how one writes the software, using Java as the example, if it matters? I'm wondering how the software changes just because it is expected that billions of users will be on the site, if at all. My understanding up to this point is that the code doesn't change, but that it is deployed on multiple servers, in a cluster, and a load balancer distributes the load, so really, on any one server/deployment, the application is just as any other standard application/website.

Answer 1

Hardware is cheap. Programming is expensive.

Answer 2

There are some programming techniques to make sure your code can handle multiple simultaneous views/updates. If you're using an existing framework, much of that work is (hopefully) done for you, but otherwise you're going to find stuff that worked for a few hundred hits an hour on one server isn't going to work when you're getting hundreds of thousands of hits and you have to deploy multiple load balancing machines.

Answer 3

Well, it is primarily an issue of hardware scaling but there are a few things to keep in mind with respect to the software involved in scaling. For example, if you are on a server farm, you'll need to work with a session management server (either via SQL Server or via a state server - which has implications in that your session variables need to be serializable).

But, in the bigger picture, there are a variety of things that you would want to do to scale to an enterprise level. For example, it becomes particularly important that you abstract out your database calls to a DAL because you may well need to adopt the use of a middleware package for high volume environments.

Answer 4

I highly recommend reading Jeff Atwood's blog on Micro-Optimization. In previous blogs he talks somewhat about how this site was created and the hardware upgrades he has had (which quickly summarized said that better hardware performs better only the extent that it is faster/better), but the real speed of a site comes from good programming, and this article seems like it should sum up some of your site programming questions quite well.