* I'd imagine the website layer is frequently static (html/js) and could just be hosted on s3/cdn. One part of scaling avoided.
> This is when we are going to want to start looking into partitioning and sharding the database.
You have to be at pretty huge scale before you really need to consider this. A giant RDS instance, some read replicas, and occasional fixing of bottlenecks will go a lonnng way. And scaling RDS is a few clicks. By the time you need to start sharding, you can probably afford a dedicated database engineer, or at least I'd hope.
* I'd imagine the website layer is frequently static (html/js) and could just be hosted on s3/cdn. One part of scaling avoided.
> This is when we are going to want to start looking into partitioning and sharding the database.
You have to be at pretty huge scale before you really need to consider this. A giant RDS instance, some read replicas, and occasional fixing of bottlenecks will go a lonnng way. And scaling RDS is a few clicks. By the time you need to start sharding, you can probably afford a dedicated database engineer, or at least I'd hope.