Help Center> GeminiDB> GeminiDB Cassandra API> Working with GeminiDB Cassandra API> Cross-region Dual-active DR> Creating a Dual-Active Relationship
Updated on 2023-11-21 GMT+08:00
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Creating a Dual-Active Relationship

If you already have an instance in one region, GeminiDB Cassandra allows you to create a dual-active DR instance in a different region, and synchronizes data between them.

This section describes how to create such a dual-active DR instance.

Precautions

  • This function is in the open beta test (OBT) phase. To use this function, contact customer service.
  • Before you create a dual-active relationship, create a destination instance in a specific region and ensure that the instance has the same or higher specifications than your existing instance. If you want to create an instance with smaller specifications than your existing instance, contact customer service and make sure that CPU and memory resources of the instance are abundant.
  • Ensure that the standby instance has no additional tables before a dual-active DR relationship is created for it.
  • The standby instance must have the same administrator password as the primary instance.
  • If you want to create a dual-active relationship again after it is removed, you need to execute the DROP statement to clear tables in the standby instance. Otherwise, the dual-active relationship cannot be created.
  • The existing instance functions as the primary instance and backs up data and transfers it to the destination instance.

Procedure

  1. Log in to the management console.
  2. In the service list, choose Databases > GeminiDB Cassandra API.
  3. On the Instances page, locate the instance that you want to create a dual-active relationship for and choose More > Create Dual-Active Relationship in the Operation column.

    Figure 1 Creating a dual-active relationship

  4. On the Create Dual-Active Relationship dialog box, locate the destination instance as the dual-active DR instance.

    Figure 2 Selecting the destination instance

    The destination instance must be in a different CIDR block from the source instance and has the same or higher specifications and no less nodes and storage space than the source, to synchronize data in real time between them and avoid subnet conflicts across regions.

  5. Click OK.
  6. On the Instances page, click before the source instance and view and manage its DR instance.

    • When the DR instance is being created, its status is Creating dual-active relationship.
    • After the creation is complete, the status changes to Available.

      You can click in the upper right corner of the page to refresh the instance status.