Geo-disaster recovery and cross-region deployment are typical scenarios in which global database networks (GDNs) are used. This topic describes the service architectures of the scenarios 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 a single 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)

The services of an enterprise may be deployed across a country or on a global scale. In this case, data must be synchronized to enable cross-region reads and writes. GDN ensures that the database can be accessed from multiple regions across the globe. In most cases, read requests are forwarded to the secondary cluster in the same region, while write requests are forwarded to the primary cluster.

  • Applicable industries: gaming, cross-border e-commerce, local services (food delivery), and new retail (outlets).
  • The following example shows the service architecture:
    • Each application deployed in a region can read data in the database that is geographically the nearest. When an application writes data to the database, the request is forwarded to the primary cluster. This can optimize the performance of data reads and writes.
    • You need to configure only one connection string for an application. You can expand your services across regions, from one data center to two, three, or even more data centers, without the need to modify the code.
    • The cluster specifications can vary across regions. For example, the cluster specifications in the China (Shanghai) and the Singapore (Singapore) regions do not need to be the same as 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 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.