Data Transmission Service:Migrate data between ApsaraDB for MongoDB instances across regions

Supported migration paths

Migration types

Billing

Required permissions

For more information about how to create and authorize a database account, see Manage user permissions on MongoDB databases.

Prerequisites

Before you begin, make sure that:

• The source instance is a standalone or replica set instance

• A public endpoint is applied for the source instance. For more information, see Apply for a public endpoint

• The destination instance is created in the target region. For more information, see Create a standalone instance, Create a replica set instance, or Create a sharded cluster instance

• The available storage space of the destination instance is 10% larger than the total data size in the source instance. This is a recommended prerequisite

• The source and destination instances use compatible MongoDB versions and storage engines. For more information, see MongoDB versions and storage engines

Before you begin

• DTS consumes resources on both the source and destination instances during full data migration, which may increase the server loads. Migrate data during off-peak hours.

• Standalone instances do not support incremental data migration. Do not write data to a standalone source instance during full data migration to maintain data consistency.

• Data written concurrently to the destination occupies 5%--10% more storage space than the data in the source.

• Make sure that the destination database does not have the same primary key as the source database. The default primary key is _id. If duplicate primary keys exist, data loss may occur. Clear conflicting data in the destination database before you start the migration without interrupting DTS services.

• ApsaraDB for MongoDB automatically updates the minor version when the current version expires or is removed from the maintenance list. This may also occur during version upgrades, data migration, configuration changes, and backup restoration.

Create a migration task

The following example migrates a replica set instance from the China (Qingdao) region to the China (Hangzhou) region.

Step 2: Configure the source and destination databases

On the Create Migration Task page, configure the following settings:

Section	Parameter	Description
--	Task Name	DTS automatically generates a task name. Specify a descriptive name for easy identification. You do not need to specify a unique task name.
Source Database	Instance Type	Select ApsaraDB for MongoDB.
	Instance Region	Select the region of the source instance. In this example, select China (Qingdao).
	MongoDB Instance ID	Select the source instance ID.
	Database Name	Enter the name of the authentication database. To use the root account, enter admin.
	Database Account	Enter the username for the source instance. For required permissions, see Required permissions.
	Database Password	Enter the password. Click Test Connectivity to verify. A Passed message indicates a successful connection. If a Failed message appears, click Check to troubleshoot.
Destination Database	Instance Type	Select MongoDB Instance.
	Instance Region	Select the region of the destination instance. In this example, select China (Hangzhou).
	MongoDB Instance ID	Select the destination instance ID.
	Database Name	Enter the name of the authentication database. To use the root account, enter admin.
	Database Account	Enter the username for the destination instance. For required permissions, see Required permissions.
	Database Password	Enter the password. Click Test Connectivity to verify. A Passed message indicates a successful connection. If a Failed message appears, click Check to troubleshoot.

Click Set Whitelist and Next.

Warning

DTS automatically or manually adds its CIDR blocks to the whitelist of the database instance or ECS security group rules. Before proceeding, take preventive measures such as strengthening username and password security, limiting exposed ports, authenticating API calls, and regularly reviewing whitelist entries. Alternatively, connect to DTS through Express Connect, VPN Gateway, or Smart Access Gateway (SAG).

Step 3: Select migration types and objects

Setting	Description
Select the migration types	Select Full Data Migration only, or select both Full Data Migration and Incremental Data Migration to keep the destination in sync during migration. Note Standalone instances do not support Incremental Data Migration. If incremental migration is not selected, do not write data to the source during full data migration to maintain data consistency.
Select the objects to be migrated	Select objects from the Available section and click the right arrow icon to move them to the Selected section. Note DTS cannot migrate data from the admin or local database. Migratable objects include databases, collections, and functions. To rename objects in the destination, use the object name mapping feature.
Specify whether to rename objects	Rename objects in the destination using object name mapping.
Specify the retry time range for a failed connection to the source or destination database	DTS retries failed connections for up to 12 hours by default. Adjust this value based on your needs. DTS charges apply during the retry period. Release the DTS instance if the source or destination database is no longer available.

Verify the migration

After the migration task is complete, verify the migration results:

• Compare the document counts between the source and destination databases to check for data loss.

• Validate that indexes are created correctly in the destination database.

• Test application connectivity to the destination instance.

Next steps

If the source instance is no longer needed, release it:

• Pay-as-you-go instance: Release the instance directly. For more information, see Release an ApsaraDB for MongoDB instance.

• Subscription instance: The instance cannot be released before the billing cycle ends.