I don't know why he lumps in AWS with Heroku. At least when I read AWS, I think of EC2, which is very similar to Linode or Digital Ocean (which he is complimentary of). I suppose there's also Elastic Beanstalk, which is more similar to Heroku, but I doubt that's what most people think of when they read 'AWS'.
> Ideally, your servers should be disposable and easily recreated. The only backups you should need are your source code (which should include any required server-setup scripts) and your database’s data.
Ugh, please don't mix server-specific setup scripts in with your app source code. Now when you want to switch from CentOS to Ubuntu, you're hosed. The server environment should be able to host your app without any modifications to the app itself, and the code that makes this environment ready to host an app should be separate from the app code, so that you can drop it into a different kind of environment at any time. This is one of the main ideas behind http://12factor.net.
Want to switch your server to a different platform? Add a new setup script for that platform to your 'setup' folder in source control.
