High-availability Edition

The High-availability Edition is a versatile cloud database edition. It uses a classic primary/secondary architecture and is suitable for more than 80% of use cases across industries such as internet services, IoT, retail, logistics, and gaming.

In the Basic Information section of an RDS instance, the Type and Edition field displays Regular instance (High-availability Edition).

Topology

Benefits

• High availability

  High-availability Edition instances have a secondary instance. The primary instance replicates data to the secondary instance in semi-synchronous or asynchronous mode, depending on the selected parameter template. If the primary instance fails, the system automatically fails over to the secondary instance.

  You can deploy the primary and secondary instances of a High-availability Edition instance in the same or different availability zones within the same region. Deploying them in different availability zones enables cross-zone disaster recovery and increases instance availability.

  Note

  If the secondary instance becomes unavailable, the primary instance initiates a real-time backup. Near the end of the backup, the system applies a global lock (FTWRL), making the primary instance read-only. This typically lasts for no more than 5 seconds.

• Comprehensive features

  High-availability Edition instances offer a complete set of features, including backup and restoration, performance optimization, and SQL Explorer. They can retain all SQL execution records for up to five years, which makes database access traceable and helps ensure the security of your core data.

Limitations

For performance reasons, the primary and secondary instances of the High-availability Edition cannot be deployed across regions.

Upgrade to High-availability edition

Basic Edition instances do not have a secondary instance for hot standby. Therefore, they may experience extended downtime during unexpected outages, configuration changes, or version upgrades. If your business requires high database availability, we recommend using the High-availability Edition.

You can select the High-availability Edition for new instances or upgrade an existing Basic Edition instance to the High-availability Edition without needing to migrate data or release the original instance.

Purchase an instance

Purchase a High-availability Edition instance

FAQ

• Can the secondary instance of a High-availability Edition instance be accessed?

  No. The secondary instance in the High-availability Edition serves only as a standby for disaster recovery and does not handle application traffic.

  Note

  However, for Cluster Edition instances, after you enable read/write splitting, the secondary instance will support read capabilities. If necessary, you can upgrade a High-availability Edition instance to a Cluster Edition instance.

• Can I downgrade a High-availability Edition instance to the Basic Edition?

  No. You cannot downgrade to the Basic Edition. As a workaround, you can purchase a new Basic Edition instance, migrate your data to the new instance, and then release the original instance.

• How can I change the data replication mode for a High-availability Edition instance?

  Currently, you can only view the data replication mode. You cannot modify the mode.

• If the secondary instance cannot keep up with the primary instance, does the replication mode degrade to asynchronous mode?

  Yes. For more information, see View the data replication mode.