A global database network (GDN) consists of multiple PolarDB clusters that are deployed across regions around the world. Data is synchronized across all clusters in each GDN. GDNs enable applications that are deployed in different regions to access databases with low latency and high stability. This topic describes how to create and release a GDN.

Prerequisites

  • The cluster must meet the following requirements:
    • The edition of the cluster is Cluster Edition.
    • The version of the cluster is PolarDB for MySQL 8.0.
  • A primary PolarDB cluster is created. For more information about how to create a PolarDB cluster, see Purchase a pay-as-you-go cluster.
  • The kernel minor version of the primary cluster is upgraded to the latest. For more information about how to upgrade the minor version, see Upgrade versions.

Considerations

  • A GDN contains one primary cluster and up to four secondary clusters. Multiple clusters can be deployed in the same zone of a region.
    Note To add more secondary clusters, Submit a ticket.
  • A cluster belongs to only one GDN.

Pricing

The cross-region data transfer traffic within a GDN is free. You are charged for only each PolarDB cluster that uses the GDN feature. For more information about the pricing of PolarDB clusters, see Billable items.

Create a GDN

  1. Log on to the PolarDB console.
  2. In the left-side navigation pane, click Global Database Network.
  3. On the Global Database Network page, click Create GDN.
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  4. In the Create GDN dialog box, specify the following parameters.
    Parameter Description
    Name The name of the GDN that you want to create. We recommend that you set a name that describes your service. It does not need to be unique.
    Primary Region The region where the primary cluster is deployed.
    Note Select the region where the primary cluster is deployed.
    Primary Cluster Select an existing cluster as the primary cluster of the GDN.
    Note

    Only PolarDB for MySQL 8.0 is supported.

  5. After you configure the preceding parameters, click OK.
    Note After you create a GDN, you can add secondary clusters. For more information, see Add and remove secondary clusters.

Release a GDN

  1. Log on to the PolarDB console.
  2. In the left-side navigation pane, click Global Database Network.
  3. Find the GDN that you want to release and click Delete in the Actions column.
    Notice
    • A GDN can be released if it contains only the primary cluster.
    • A GDN cannot be restored after it is released. Proceed with caution.
    • Applications that are connected to GDN endpoints cannot access databases. Modify the application code to change the connection string of the GDN at the earliest opportunity.
  4. In the Delete GDN message, click OK.

FAQ

  • How many GDNs can I create for an Alibaba Cloud account?

    The number of GDNs that you can create is unlimited.

  • After a GDN is created, can I change the primary cluster of the GDN?
    No, you cannot change the primary cluster after the GDN is created. You can create another GDN, select the required cluster as the primary cluster, and then release the current GDN.
    Note Before you release the GDN, remove all secondary clusters from the GDN.