Geo-disaster recovery and cross-region deployment are typical scenarios in which global database networks (GDNs) are used. This topic also describes the service architectures and how to deploy GDNs in these scenarios.

Geo-disaster recovery

The geo-disaster recovery feature allows you to achieve high availability across regions. This enhances data security and improves service availability. If a data center breakdown occurs, services can be rapidly recovered. Architectures can be implemented, such as three data centers across two zones, four data centers across two zones, and six data centers across three zones.

  • Typical industries include banking, securities, insurance, and fintech.
  • The following example shows the service architecture of three data centers across two zones:
    The databases are deployed in two PolarDB clusters: 1
    • The cluster in the China (Beijing) region is deployed in two zones: AZ 1 and AZ 2.
    • The cluster in the China (Shanghai) region is deployed in one zone.

    The application is deployed in the China (Beijing) region and performs local read and write operations on the database in AZ 1.

    • If AZ 1 in the China (Beijing) region fails, the service is preferentially switched to AZ 2 in the China (Beijing) region.
    • If AZ 1 and AZ 2 in the China (Beijing) region fail, the service is switched to AZ 3 in the China (Shanghai) region.

Cross-region deployment (active geo-redundancy)

In some cases, services of enterprises are deployed across the country or on a global scale. Therefore, data must be synchronized to achieve cross-region reads and writes. The database can be accessed from global regions. However, read and write requests are sent to the clusters that are deployed in the same region as the application.

  • Applicable industries: gaming, cross-border e-commerce, local services (takeout), and new retail (outlets).
  • The following example shows the service architecture:
    • The applications in each region read data from and write data to the database that is deployed in the same region. This ensures optimal performance.
    • You need to configure only one connection string for an application. You can expand your services cross regions, from one data center to two, three, or even more data centers, without modifying the code.
    • The cluster specifications in the China (Shanghai) and the Singapore (Singapore) regions do not need to be consistent with the specifications in the China (Beijing) region. You can select the specifications based on your requirements.
2

Procedure

  1. Create a GDN and select an existing cluster as the primary cluster in the GDN. For more information, see Create and release a GDN.
  2. In the GDN, add a secondary cluster. For more information, see Add a secondary cluster.
  3. Connect to the GDN. For more information, see Connect to a GDN.

For more information about the best practices for deploying GDNs across regions, see Best practices for deploying a GDN across regions.