Azure Container Storage is a container native, microservices-based storage service providing unified volume management across different cloud storage backends, enabling consistency and portability. Azure Elastic SAN, which is one such backend, is a purpose-built, highly available block storage solution designed to scale to millions of IOPS at low ms latency. In this talk, we will deep dive into how Azure Container Storage uses Azure Elastic SAN to provide elastic bursting of stateful pods for large scale data processing at low cost. We will reveal technical designs and innovations in the Elastic SAN architecture behind the massive control and data plane scale. In addition, we will use this example to highlight how different SAN solutions can integrate with Azure Container Storage.