This describes how to deploy a Global Database Network (GDN) across regions.

Deployment plan

Create a GDN

After you create a GDN, it contains a primary cluster. For more information, see Create a GDN.

Note The cross-region data transfer within a GDN is free of charge. You are charged for only PolarDB clusters in the GDN. For more information about the pricing of PolarDB clusters, see Billable items.

Add a secondary cluster

Add a secondary cluster to the GDN to form a global database network. For more information, see Add a secondary cluster.

  • When you create a secondary cluster, we recommend that you set the same node specifications as those of the primary cluster to ensure low-latency synchronization. You can specify the number of read-only nodes based on read requests to the secondary cluster that is deployed in the same region as the client.
  • GDN supports low-latency synchronization across regions. Secondary clusters automatically synchronize data from the primary cluster. You do not need to purchase additional services, such as Data Transmission Service (DTS).

Connect to a GDN

After the GDN is created, you can use the cluster endpoint to connect to and manage the GDN. For more information, see Connect to a GDN.

(Optional) Purchase a storage plan

You are eligible for storage plans when you use the following resources:

  • Cluster storage

    The storage of each PolarDB cluster in a Global Database Network (GDN) is charged based on the data volume and retention period. If you require a larger storage capacity, such as 1,000 GB or more, we recommend that you use storage plans to reduce costs.

  • Level-1 backups that exceed the free quota

    Storage plans are applied to all PolarDB clusters that belong to your account. The remaining capacity of a storage plan is automatically applied to the overage of level-1 backups at a ratio of 1:1.6 when the free quota is exhausted. In this case, every 1 GB of the storage plan is used to deduct 1.6 GB of level-1 backup storage. If the remaining capacity of the storage plan is insufficient to offset the overage of level-1 backups, the overage is charged on a pay-as-you-go basis. For more information about storage plans, see Storage plans.

For more information, see Purchase a storage plan.

  • You can select the following types of storage plans: storage plans that apply to regions inside mainland China, and storage plans that apply to China (Hong Kong) and regions outside China. You can purchase only one storage plan for each type.
  • A storage plan can be used by all the clusters in the regions that are specified by the Plan Type parameter. You can select Mainland China or China (Hong Kong) and regions outside China. For more information, see Scale-out and scale-in.
  • If the capacity of your storage plan is insufficient, you can upgrade the storage plan. However, storage plans cannot be downgraded.
  • You are charged for the storage that is not covered by the storage plan on a pay-as-you-go basis.

For example, each cluster in the GDN requires 300 GB of storage. You can purchase a 500 GB of mainland China storage plan to deduct the storage of the primary cluster in the China (Beijing) region and the secondary cluster in the China (Shanghai) region. Then, you can purchase a 300 GB of China (Hong Kong) and regions outside China storage plan to deduct the storage of the secondary cluster in Singapore. The 100 GB of storage that exceeds the capacity of the storage plan is charged on a pay-as-you-go basis.