Cloud-native engineering talks frequently focus on implementing and operating the stateless parts of applications. Designing and deploying stateful services such as databases and message brokers, involves additional concerns: we must ensure data durability as well as service availability, and consider the cost/performance tradeoffs of placing data on local disk, block storage, or object storage.

This talk delves into the often-overlooked complexities of stateful cloud service design, using Neon Serverless Postgres as a case study. We will discuss the key decision points: where do you put your data, and how many copies? How do we ensure availability when starting a new node with an empty cache drive? How can we efficiently scale a service that requires local disk storage? Additionally, we'll examine Kubernetes' role in this landscape and the cost implications of achieving data durability across multiple availability zones or regions.