Real-Time Migration

In real-time migration, you only need to configure the source database, destination database, and migration objects. DRS will help you compare and analyze data so you can determine when to migrate with minimal service disruption.

Only whitelisted users can use this function. To use this function, submit a service ticket. In the upper right corner of the management console, choose Service Tickets > Create Service Ticket to submit a service ticket.

Supported Database Types

For details about the supported databases, versions, and migration types, see Supported Databases.

Supported Network Types

DRS supports data migration through a Virtual Private Cloud (VPC), Virtual Private Network (VPN), Direct Connect, or public network. Table 1 lists the application scenarios of each network type and required preparations, and Table 2 lists the supported network types of each migration scenario.

**Table 1** Network types
Network Type	Application Scenario	Preparations
VPC	Migrations between cloud databases in the same region	The source and destination databases must be in the same region. The source and destination databases can be in either the same VPC or in different VPCs. If source and destination databases are in the same VPC, they can communicate with each other by default. Therefore, you do not need to configure a security group. If the source and destination databases are not in the same VPC, the CIDR blocks of the source and destination databases cannot be duplicated or overlapped, and the source and destination databases are connected through a VPC peering connection. DRS automatically establishes a route through a single IP address when you test the network connectivity. DRS does not support communication between the source database and destination database over a VPC across tenants. If necessary, you can create a VPC peering connection and select VPN for Network Type to enable communication between the source and destination databases. For details about how to create a VPC peering connection, see Virtual Private Cloud User Guide.
VPN	Migrations 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 migration, ensure that the VPN network is accessible. For more information about VPN, see Getting Started with Virtual Private Network.
Direct Connect	Migrations 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. For more information about Direct Connect, see Getting Started with Direct Connect.
Public network	Migrations from on-premises 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 replication instance to the whitelist of the source database for inbound traffic. If destination databases and the replication 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 replication instance. If SSL is not enabled, migrating confidential data is not recommended.

**Table 2** Network types
Migration Direction	Source DB	Destination DB	VPC	Public Network	VPN or Direct Connect
To the cloud	MySQL	MySQL	Supported	Supported	Supported
		DDM	Supported	Supported	Supported
		GaussDB(for MySQL)	Supported	Supported	Supported
	MongoDB	DDS	Supported	Supported	Supported
	MongoDB	GaussDB(for Mongo) NOTE: Only whitelisted users can use this function.	Supported	Supported	Supported
	MySQL schema and logic table	DDM	Supported	Supported	Supported
	Redis	GaussDB(for Redis) NOTE: Only whitelisted users can use this function.	Supported	Supported	Supported
From the cloud	MySQL	MySQL	Supported	Supported	Supported
	DDS	MongoDB	Supported	Supported	Supported
	GaussDB(for Redis)	Redis NOTE: Only whitelisted users can use this function.	Supported	Supported	Supported

Migration Objects

DRS allows you to migrate objects at different levels. The following table lists the supported migration objects.

**Table 3** Supported migration objects
Direction	Source DB	Destination DB	Full Migration	Table-Level Migration	Database-Level Migration
To the cloud	MySQL	MySQL	Supported	Supported	Supported
		GaussDB(for MySQL)	Supported	Supported	Supported
		DDM	Not supported	Supported	Not supported
	MongoDB	DDS	Supported	Supported	Supported
	MongoDB	GaussDB(for Mongo) NOTE: Only whitelisted users can use this function.	Supported	Supported	Supported
	MySQL schema and logic table	DDM	Not supported	Supported	Not supported
	Redis	GaussDB(for Redis) NOTE: Only whitelisted users can use this function.	Not supported	Not supported	Supported
From the cloud	MySQL	MySQL	Supported	Supported	Supported
	DDS	MongoDB	Supported	Supported	Supported
	GaussDB(for Redis)	Redis NOTE: Only whitelisted users can use this function.	Supported	Not supported	Not supported

Advanced Features

DRS supports multiple features to ensure successful real-time migration.

**Table 4** Advanced features
Feature	Description
Flow control	Allows you to limit the overall migration speed to make the impact of migration on bandwidth and database I/O controllable. Flow control mode takes effect only during a full migration.
Account migration	Allows you to migrate accounts, permissions, and passwords.
Parameter comparison	Checks the consistency of common parameters and performance parameters between source and destination databases to ensure that the migrated service is running properly.