This topic describes how to migrate a standalone instance or a replica set instance across regions by using Data Transmission Service (DTS). DTS allows you to migrate full data and incremental data without service disruptions.
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 You cannot use DTS to migrate incremental data of 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 region. For more information, see Create a standalone instance, Create a replica set instance, or Create a sharded cluster instance.
Note The storage capacity of the destination instance must be larger than the occupied storage space of the source instance.
Background information
You may need to migrate the data of an ApsaraDB for MongoDB instance across regions in the following situations:
- Change a business structure.
- Use an ApsaraDB for MongoDB instance to provide database services for applications deployed on an ECS instance. However, the ApsaraDB for MongoDB instance and the ECS instance are not in the same region.
An ApsaraDB for MongoDB instance in the China (Qingdao) region is migrated to an ApsaraDB for MongoDB instance in the China (Hangzhou) region in this example.
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 uses resources of the source and destination instances during full data migration. This may increase the load of the database server. If the data volume is large or the specification is low, the database server may become unavailable. We recommend that you migrate your data during off-peak hours to avoid business interruptions.
- To ensure data consistency, we recommend that you do not write data to the source instance while full data migration of a standalone instance is in progress.
- If the source and destination instances run different database versions or storage engines, make sure that the instances do not have compatibility issues between them before you start the migration. For more information about the database versions and storage engines 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
|
Permissions required for database accounts
| Data source | Full data migration | Incremental data migration |
|---|---|---|
| Source ApsaraDB for MongoDB instance | Read permissions on the source database | Read permissions on the source database, admin database, and local database |
| Destination ApsaraDB for MongoDB instance | Read and write permissions on the destination database | 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
- At the top of the Migration Tasks page, select the region where the destination ApsaraDB for MongoDB instance is deployed.
- Configure the source and destination databases for the data migration task.
Section Parameter Description N/A Task Name The name of the migration task. DTS automatically generates a task name. We recommend that you set a descriptive name that makes it easy to identify. Task names do not have to be unique. Source Database Instance Type The category of the source instance. In this example, select ApsaraDB for MongoDB. Instance Region The region where the source instance is deployed. In this example, select China (Qingdao). MongoDB Instance ID The ID of the source ApsaraDB for MongoDB instance. Database Name The name of the database corresponding to the username if authentication is enabled. Note If the database account is root, enter admin.Database Account The account that is used to log on to the source database. For more information about the permissions that are required for the account, see Permissions required for database accounts. Database Password The password of the source database account. Note After you specify the source database parameters, click Test Connectivity next to Database Password to verify whether the information is valid. If the information is valid, the Passed message appears. If the information is invalid, the Failed message appears, and you must click Check next to the Failed message to modify the information.Destination Database Instance Type The category of the destination instance. In this example, select MongoDB Instance. Instance Region The region where the destination instance is deployed. In this example, select China (Hangzhou). MongoDB Instance ID The ID of the destination instance. In this example, select the ID of the destination ApsaraDB for MongoDB instance. Database Name The name of the database corresponding to the username if authentication is enabled. Note If the database account is root, enter admin.Database Account The account that is used to log on to the destination database. In this example, enter the destination ApsaraDB for MongoDB database account. For more information about the permissions that are required for the account, see Permissions required for database accounts. Database Password The password of the destination database account. Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the information is valid. If the information is valid, the Passed message appears. If the information is invalid, the Failed message appears, and you must click Check next to the Failed message to modify the information. - Select the migration types and objects to be migrated.
Parameter Description Migration Types - If you want to migrate all data, select Full Data Migration.
- If you want to migrate data without interruptions to your business, select both 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, do not write data into the source database during full data migration. This ensures data consistency between the source and destination databases.
Objects - In the Available section, select the objects you want to migrate and then click the
icon to move them to the Selected section.
Note Data in the admin and local databases cannot be migrated. - A migration object can be a database, collection, or function.
- By default, the name of an object remains unchanged after migration. If you want a different object name after migration, use the object name mapping feature provided by DTS. For more information, see Object name mapping.
Specify whether to rename object names You can use the object name mapping feature to change the names of the objects that are synchronized to the destination instance. For more information, see Object name mapping. Specify the retry time for failed connection 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. - In the lower-right corner of the page, click Precheck.Notice
- Before you can start the data migration task, a precheck is performed. DTS can migrate data only if the precheck is past.
- If the precheck fails, click the
icon next to each failed item to view details. Fix the issues as prompted and run
the precheck again.
- 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.- 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.
- After the status of incremental data migration changes to The migration task is not delayed, manually stop the migration task.
- Full data migration
What to do next
Determine whether to release the source instance.
- If the source instance uses the pay-as-you-go billing method, release the source instance. For more information, see Release an ApsaraDB for MongoDB instance.
- If the source instance uses the subscription billing method, you cannot release the source instance.