Blockchain System Design Considerations

Introduction

Most engineers think blockchain is just about cryptography and distributed consensus. The real complexity lies in managing eventually consistent state across thousands of adversarial nodes while maintaining sub-second query performance.

The State Explosion Problem

Here’s what Bitcoin’s engineers discovered: storing every transaction forever creates a quadratic growth problem. With 500 million transactions, full nodes need 450GB of disk space. Ethereum hit this faster—their state trie grew to 800GB in just 6 years. The solution? Separate the execution layer from the data availability layer.