B is the answer. https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concepts-high-availability#limitations Here are some considerations to keep in mind when you use high availability: - High availability isn't supported in the burstable compute tier.

B. General Purpose The General Purpose compute tier provides a balance between performance and cost. It is suitable for most common workloads and offers a good combination of CPU and memory resources. It provides high availability and fault tolerance by utilizing Azure's infrastructure across multiple datacenters. This ensures that the databases remain accessible even if a datacenter fails. The Burstable compute tier (option A) is designed for workloads with variable or unpredictable usage patterns. It provides burstable CPU performance but may not be the optimal choice for ensuring availability during a datacenter failure. The Memory Optimized compute tier (option C) is designed for memory-intensive workloads that require high memory capacity. While it provides excellent performance for memory-bound workloads, it may not be necessary for minimizing costs or meeting the specified requirements.

Based on the requirements, the Burstable compute tier would be the most suitable choice for the Azure Database for MySQL Flexible Server configuration. The Burstable tier is ideal for workloads that don’t need continuous full compute capacity. It provides better cost optimization controls with the ability to stop/start the server. Moreover, the flexible server architecture allows users to opt for high availability within a single availability zone and across multiple availability zones, ensuring that the databases remain accessible even if a datacenter fails.

I would go for B Flexible Server is a fully managed production-ready database service designed for more granular control and flexibility over database management functions and configuration settings. The flexible server architecture allows users to opt for high availability within a single availability zone and across multiple availability zones. Flexible servers provide better cost optimization controls with the ability to stop/start the server and burstable compute tier, ideal for workloads that don't need full compute capacity continuously. Flexible Server also supports reserved instances allowing you to save up to 63% cost, which is ideal for production workloads with predictable compute capacity requirements.

I think answer is correct. https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concepts-service-tiers-storage

The databases must be accessible if a datacenter fails! Azure availability zones are at least three physically separate groups of datacenters within each Azure region. If one datacenter fails then the data will be available in other datacenter in same zone. So the answer is correct. https://learn.microsoft.com/en-us/azure/reliability/reliability-postgresql-flexible-server

Tested in Lab, B - General Purpose is correct. Burstable doesn't support high availability. Only General Purpose or Business Critical

A. Burstable. It provides the lowest cost. Both Burstable and General Purpose provide Zone Redundancy https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concepts-service-tiers-storage https://azure.microsoft.com/en-us/pricing/details/mysql/

Got this on Sept. 29, 2023

I had question at 24th Sep 2023

When trying to enable high availability with the Burstable tier, I see this message: "High availability is not supported with the compute tier choice. If you would like to configure high availability, the compute tier will be upgraded to the General Purpose compute tier or you may choose a different compute tier by clicking 'Configure Server' below." So, General Purpose is the answer to minimize costs.

General purpose provides Zone redundanty

Zone redundancy requirement which General purpose provides.

Burstable is not zone redundant - so B is correct

High availability isn't supported in the burstable compute tier. https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concepts-high-availability#limitations

Has to be B, if the requirement states "The databases must be accessible if a datacenter fails.". Checked in portal, could not set up high availability unless I switched from burstable to Gen-Purpose.

Only general-purpose tier supports Zone Redundant. tested in portal.