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.
Prerequisites
- Available resources are deployed in two or more zones within the region of the PolarDB cluster. The multi-zone deployment feature is not available in the following regions: US (Silicon Valley), US (Virginia), Philippines (Manila), South Korea (Seoul), Australia (Sydney), China (Qingdao), China (Chengdu), and China (Hohhot).
- The destination zone has sufficient compute resources.
- The hot standby cluster feature is enabled.
Multi-zone architecture
If your cluster is deployed across multiple zones, data is distributed in multiple zones. The primary zone and a secondary zone individually contain three replicas of data. This way, a total of six replicas of data are saved, which ensures high SLA reliability. Currently, the compute nodes of a cluster are located in the primary zone. Hot standby clusters in the secondary zone are used for failovers when the primary zone fails. If the primary zone fails, you can switch services from the primary zone to the secondary zone. For more information, see Change the primary zone and vSwitch of a cluster.
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 multi-zone cluster, see Purchase a pay-as-you-go cluster and Purchase a subscription cluster.
Pricing for multi-zone deployment
You are not charged additional fees for the multi-zone deployment feature.
View the zones of a cluster
