Migrate data between ApsaraDB for MongoDB instances across regions - User Guide| Alibaba Cloud Documentation Center

This topic describes how to migrate a standalone instance or a replica set instance across regions by using Data Transmission Service (DTS). You can perform full data migration and incremental data migration for a replica set instance. You can perform only full data migration for a standalone instance.

Prerequisites

The source instance is a standalone instance or a replica set instance. If the source instance is a sharded cluster instance, we recommend that you use the built-in tools of MongoDB to migrate data. For more information, see Migrate a self-managed MongoDB database to ApsaraDB for MongoDB by using tools provided by MongoDB.

Note DTS does not support incremental data migration from a standalone instance. For more information, see Migration types.
A public endpoint is applied for the source instance. For more information, see Apply for a public endpoint for an ApsaraDB for MongoDB instance.
The destination instance is created in the destination region. For more information, see Create standalone instances, Create replica set instances, or Create a sharded cluster instance.

Note The available storage space of the destination instance must be larger than the total size of the data in the source instance.

Background information

You may need to migrate the data of an ApsaraDB for MongoDB instance across regions in the following situations:

Restructure your business.
Use an ApsaraDB for MongoDB instance to provide database services for applications deployed on an Elastic Compute Service (ECS) instance. However, the ApsaraDB for MongoDB instance and the ECS instance are not in the same region.

In this example, an ApsaraDB for MongoDB instance in the China (Qingdao) region is migrated to an ApsaraDB for MongoDB instance in the China (Hangzhou) region.

Migrate data between ApsaraDB for MongoDB instances across regions

Note This example describes only how to migrate data from the source instance. After data is migrated, you can release the source instance if you no longer need the source instance.

Precautions

DTS consumes the resources of the source and destination instances during full data migration. This may increase the loads of the database servers. If you migrate a large volume of data or the server specifications cannot meet your requirements, database services may become unavailable. Before you migrate data, evaluate the impact of data migration on the performance of the source and destination databases. We recommend that you migrate data during off-peak hours.
DTS does not support incremental data migration from a standalone instance. To ensure data consistency, do not write data to the source instance during full data migration.
If the source and destination MongoDB databases use different versions or storage engines, make sure that your applications can run on both databases. For more information about the versions and storage engines that are supported by ApsaraDB for MongoDB, see MongoDB versions and storage engines.
To ensure better performance and stability of the instance, the system will upgrade the minor version to the latest version by default. If the minor version of your instance expires or is not included in the maintenance list and the instance is upgraded, migrated, changed, Created from a backup, Created by point-in-time, or performed Restore data to a new ApsaraDB for MongoDB instance.

Pricing


Migration type	Instance fee	Internet traffic fee
Full data migration	Free of charge	Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see DTS pricing.
Incremental data migration	Charged. For more information, see DTS pricing.

Migration types


Migration type	Description
Full data migration	All data of the migration objects is migrated from the source instance to the destination instance. Note The following types of objects are supported: database, collection, and index.
Incremental data migration	Updated data of the migration objects is synchronized from the source instance to the destination instance. Note The create and delete operations that are performed on databases, collections, and indexes can be synchronized. The create, delete, and update operations that are performed on documents can be synchronized.

Permissions required for database accounts


Database	Full data migration	Incremental data migration
Source ApsaraDB for MongoDB instance	The read permissions on the source database	The read permissions on the source database, the admin database, and the local database
Destination ApsaraDB for MongoDB instance	The read and write permissions on the destination database	The read and write permissions on the destination database

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

Procedure

Log on to the ApsaraDB for MongoDB console.
In the upper-left corner of the page, select the resource group and the region of the target instance.
In the left-side navigation pane, click Replica Set Instances or Sharded Cluster Instances.
Find the target instance and click its ID.
At the top of the Migration Tasks page, select the region where the destination ApsaraDB for MongoDB instance is deployed.

On the Create Migration Task page, create a data migration task.

Configure the source and destination databases.


Section	Parameter	Description
N/A	Task Name	DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
Source Database	Instance Type	Select ApsaraDB for MongoDB.
	Instance Region	Select the region where the source ApsaraDB for MongoDB instance resides. In this example, select China (Qingdao).
	MongoDB Instance ID	Select the ID of the source ApsaraDB for MongoDB instance.
	Database Name	Enter the name of the authentication database. The database account is created in this database. Note If the database account is root, enter admin.
	Database Account	Enter the database account of the source ApsaraDB for MongoDB instance. For more information about the permissions that are required for the account, see Permissions required for database accounts.
	Database Password	Enter the password of the database account. Note After you specify the source database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the source database parameters based on the check results.
Destination Database	Instance Type	Select MongoDB Instance.
	Instance Region	Select the region where the destination ApsaraDB for MongoDB instance resides. In this example, select China (Hangzhou).
	MongoDB Instance ID	Select the ID of the destination ApsaraDB for MongoDB instance.
	Database Name	Enter the name of the authentication database. The database account is created in this database. Note If the database account is root, enter admin.
	Database Account	Enter the database account of the destination ApsaraDB for MongoDB instance. For information about the permissions that are required for the account, see Permissions required for database accounts.
	Database Password	Enter the password of the database account. Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the destination database parameters based on the check results.

In the lower-right corner of the page, click Set Whitelist and Next.

Note DTS adds the CIDR blocks of DTS servers to the whitelists of the source and destination ApsaraDB for MongoDB instances. This ensures that DTS servers can connect to the source and destination ApsaraDB for MongoDB instances. After data migration is complete, you can remove the CIDR blocks of DTS servers from the whitelists. For more information, see Configure a whitelist for a sharded cluster instance.

Select the migration types and the objects to be migrated.


Setting	Description
Select the migration types	To perform only full data migration, select only Full Data Migration. To ensure service continuity during data migration, select Full Data Migration and Incremental Data Migration. Note DTS does not support incremental data migration for standalone instances. If Incremental Data Migration is not selected, we recommend that you do not write data to the source instance during full data migration. This ensures data consistency between the source and destination instances.
Select the objects to be migrated	Select one or more objects from the Available section. Click the icon to move the objects to the Selected section. Note DTS cannot migrate data from the admin or local database. You can select databases, collections, or functions as the objects to be migrated. By default, after an object is migrated to the destination instance, the name of the object remains unchanged. You can use the object name mapping feature to rename the objects that are migrated to the destination instance. For more information, see Object name mapping.
Specify whether to rename objects	You can use the object name mapping feature to rename the objects that are migrated to the destination instance. For more information, see Object name mapping.
Specify the retry time for failed connections to the source or destination database	By default, if DTS fails to connect to the source or destination database, DTS retries within the next 12 hours. You can specify the retry time based on your needs. If DTS reconnects to the source and destination databases within the specified time, DTS resumes the data migration task. Otherwise, the data migration task fails. Note When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time based on your business needs. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.

Click Buy and Start to start the migration task.
- Full data migration
  Do not manually stop a task during full data migration. Otherwise, the system may fail to perform a full data migration. Wait until the full data migration task automatically stops.
- Incremental data migration
  An incremental data migration task does not automatically end. You must manually end the task.
  
  Note Select an appropriate time to manually stop the migration task. For example, you can stop the migration task during off-peak hours or before you switch your workloads to the destination ApsaraDB for MongoDB instance.
  1. Wait until Incremental Data Migration and The migration task is not delayed appear in the progress bar of the migration task. Then, stop writing data to the source database for a few minutes. The delay time of incremental data migration may be displayed in the progress bar.
  2. After the status of incremental data migration changes to The migration task is not delayed, manually stop the migration task.