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PolarDB:Multi-zone deployment architecture

Last Updated:Jul 10, 2024

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 faults in data centers. 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 in which the PolarDB for MySQL cluster is deployed. The multi-zone deployment feature is not available in the following regions: Philippines (Manila), South Korea (Seoul), Australia (Sydney), China (Qingdao), China (Chengdu), China (Hohhot), and Thailand (Bangkok).

  • The destination zone has sufficient computing resources.

  • The hot replica feature is enabled for the read-only nodes in a PolarDB for MySQL cluster.

Multi-zone architecture

If your cluster is deployed across multiple zones, data is distributed in multiple zones. The primary zone and a secondary zone each contain three replicas of data. This way, a total of six replicas of data are saved, which ensures high service level agreement (SLA) reliability. Compute nodes must be deployed in the primary zone. The cluster that contains the read-only nodes for which the hot replica feature is enabled in a secondary zone is deployed for a failover when the primary zone fails.

The following figure shows the multi-zone architecture.Multi-zone architecture

Note

Available resources are deployed in two or more zones within the region in which the PolarDB for MySQL cluster is deployed. 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), China (Hohhot), and Thailand (Bangkok).

Build an architecture for multi-zone deployment

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

On the Basic Information page of the cluster, you can view the value of the Zones parameter for the cluster.Zones