Blockchain Scalability 的内涵
Blockchain 要处理的核心挑战：
- replicated computation
- replicated storage
- consensus overhead
Scalability 解决方案：Every node process all partial TXs, store all partial data, with more efficient consensus. 这要求
- State validity
- Data availability
- Byzantine Adversary
Sharding 切片
Horizontally scale by partitioning transaction processing into shards, and parallelizing their execution