What's the recommended solution for the deployment of three geo-distributed data centers?

The architecture of TiDB guarantees that it fully supports geo-distribution and multi-activeness. Your data and applications are always-on. All the outages are transparent to your applications and your data can recover automatically. The operation depends on the network latency and stability. It is recommended to keep the latency within 5ms. Currently, TiDB already has similar use cases. For details, see Three Data Centers in Two Cities Deployment.