AnalyticDB for MySQL introduces services in elastic mode with the support of cloud platform scalability.
AnalyticDB for MySQL in reserved mode utilizes a shared-nothing architecture that provides good scalability and concurrency. Computing and storage resources are coupled in the backend. The frontend and backend share the same resources. Storage capacities and computing capabilities are related to the number of nodes. You can scale nodes in or out to adjust your resource requirements. However, you cannot flexibly specify the ratio of computing resources to storage resources to meet requirements of different business loads. Additionally, if you scale nodes, a large amount of data must be migrated. This can take a long period of time and affect current system loads. If the ratio of computing resources to storage resources cannot be flexibly specified, cost-effectiveness is decreased.
AnalyticDB for MySQL in elastic mode utilizes an architecture that separates computing resources from storage resources in the backend and provides a unified service-based serverless storage layer. The computing layer can be separately scaled and provide good performance as that in reserved mode. After computing and storage resources are decoupled, you can separately scale computing resources and storage capacities to control total costs. If you scale computing resources, data migration is not required, which provides better experiences in scaling resources.