What is sharding and why is it important?

Question

I think I understand sharding to be putting back your sliced up data (the shards) into an easy to deal with aggregate that makes sense in the context. Is this correct?

Answer 1

In my opinion the application tier should have no business determining where data should be stored

This is a good rule but like most things not always correct.

When you do your architecture you start with responsibilities and collaborations. Once you determine your functional architecture, you have to balance the non-functional forces.

If one of these non-functional forces is massive scalability, you have to adapt your architecture to cater for this force even if it means that your data storage abstraction now leaks into your application tier.