Real-Time Disaster Recovery

Database Types

DRS supports disaster recovery (DR) management for the following types of databases.

**Table 1** Database types
DR Direction	Data Flow	Service Database	DR Database	DR DB Instance Type
Current cloud as standby	MySQL->MySQL	On-premises databases Databases on an ECS Databases on other clouds RDS for MySQL instances	RDS for MySQL instances	Single DB instance Primary/Standby DB instance
Current cloud as active	MySQL->MySQL	RDS for MySQL instances	On-premises databases ECS databases Databases on other clouds RDS for MySQL instances	Single DB instance Primary/Standby DB instance

Database Versions

**Table 2** Database versions
DR Direction	Data Flow	Service Database Version	DR Database Version
Current cloud as standby	MySQL->MySQL	MySQL 5.6.x MySQL 5.7.x MySQL 8.0.x	MySQL 5.6.x MySQL 5.7.x MySQL 8.0.x
Current cloud as active	MySQL->MySQL	MySQL 5.6.x MySQL 5.7.x MySQL 8.0.x	MySQL 5.6.x MySQL 5.7.x MySQL 8.0.x

Network Preparations

DRS supports disaster recovery through a Virtual Private Network (VPN), Direct Connect, or public network. Table 3 lists the application scenarios of each network type and required preparations.

**Table 3** Network types
Network Type	Application Scenario	Preparations
VPN	Disaster recovery from on-premises databases to cloud databases or between cloud databases across regions	Establish a VPN connection between your local data center and the VPC that hosts the destination database. Before disaster recovery, ensure that the VPN network is accessible.
Direct Connect	Disaster recovery from on-premises databases to cloud databases or between cloud databases across regions	Use a dedicated network connection to connect your data center to VPCs.
Public network	Disaster recovery from on-premises databases or other cloud databases to destination databases.	To ensure network connectivity between the source and destination databases, perform the following operations: Enable public accessibility. Enable public accessibility for the source database based on your service requirements. Configure security group rules. Add the EIPs of the disaster recovery instance to the whitelist of the source database for inbound traffic. If destination databases and the DR instance are in the same VPC, they can communicate with each other by default. You do not need to configure a security group. NOTE: The IP address on the Configure Source and Destination Databases page is the EIP of the DR instance. If SSL is not enabled, backing up confidential data for disaster recovery is not recommended.