This topic describes the typical scenarios of global database networks (GDNs).

Geo-disaster recovery

The geo-disaster recovery feature ensures cross-region high availability and improves data security and system availability. If a data center-level failure 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 Internet finance.
  • The following example shows the service architecture of three data centers across two zones:
    The database consists of two PolarDB clusters:
    • 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)

Users of enterprises are distributed all over the country and the world. Therefore, data must be synchronized to realize cross-region reads and writes. The same database can be accessed from regions around the globe, but read and write requests are sent to local clusters whenever possible.

  • Typical industries are gaming, cross-border e-commerce, local livelihood (food delivery), and new retail (stores).
  • The following example shows the service architecture:
    • The applications in each region directly read and write data from or into the database in the nearby region. This delivers the best performance.
    • You need only to configure one connection address for an application. You do not need to modify code to smoothly expand your business to more regions, and from one data center to two, three, or even more data centers.
    • 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 needs.