Modern distributed database architectures have evolved to address scalability, consistency, and fault tolerance. The layered architecture separates concerns into distinct roles or layers, each responsible for a specific function, balancing scalability, consistency, and operational complexity. This design combines the benefits of centralized coordination with the scalability of distributed systems. However, it also introduces tradeoffs such as increased latency and system complexity. In contrast, the shared-storage architecture offloads storage to object storage systems like S3, simplifying development and offering infinite scalability, elasticity, and durability. Nevertheless, this approach is associated with increased latency and network dependency. Hybrid architectures are emerging to balance flexibility and performance, with OceanBase and TiDB supporting both shared-nothing and shared-storage modes. Ultimately, understanding the tradeoffs of modern distributed database architectures empowers developers and system architects to choose the right tools for their unique workloads.