PolarDB for MySQL allows you to deploy a cluster across multiple zones. Compared with single-zone clusters, multi-zone clusters can enhance disaster recovery capabilities and withstand data center-level faults. This topic describes how to deploy a cluster across multiple zones and change the primary zone.
- The region in which the cluster is deployed contains two or more zones.
- The destination zone has sufficient computing resources.
When a multi-zone cluster is deployed, data is distributed across zones. Compute nodes must be deployed in the primary zone. PolarDB reserves sufficient resources in a secondary zone to implement a failover if the primary zone fails.
The following figure shows the multi-zone deployment architecture.
Establish a multi-zone deployment architecture
By default, if the prerequisites are met, a multi-zone cluster is created. For more information about how to create a cluster, see Purchase a pay-as-you-go cluster and Purchase a subscription cluster.
The existing single-zone clusters are upgraded to multi-zone clusters. The upgrades are automatically performed by migrating data online. This does not affect your services.