This topic describes how to migrate data from an ApsaraDB for MongoDB instance (replica set architecture) to another ApsaraDB for MongoDB instance (replica set architecture or sharded cluster architecture) by using Data Transmission Service (DTS).

Supported source and destination databases

Note The access methods of the source and destination databases must be the same. For example, both the source and destination instances are ApsaraDB for MongoDB instances.
Source database (replica set architecture) Destination database (replica set architecture or sharded cluster architecture)
ApsaraDB for MongoDB ApsaraDB for MongoDB
Self-managed database that is hosted on Elastic Compute Service (ECS) Self-managed database that is hosted on ECS
Self-managed database that is connected over Express Connect, VPN Gateway, or Smart Access Gateway Self-managed database that is connected over Express Connect, VPN Gateway, or Smart Access Gateway
Self-managed database with a public IP address Self-managed database with a public IP address

In this example, the source database is an ApsaraDB for MongoDB instance (replica set architecture) and the destination database is an ApsaraDB for MongoDB instance (replica set architecture or sharded cluster architecture). You can also follow the procedure to configure data migration tasks for other types of MongoDB databases.

Prerequisites

  • The source ApsaraDB for MongoDB instance (replica set architecture) and the destination ApsaraDB for MongoDB instance (replica set architecture or sharded cluster architecture) are created. For more information, see Create replica set instances and Create a sharded cluster instance.
    Note For more information about supported MongoDB versions, see Overview of data migration scenarios.
  • The available storage space of the destination ApsaraDB for MongoDB instance is larger than the total size of the data in the source ApsaraDB for MongoDB instance.
  • If the destination ApsaraDB for MongoDB instance is deployed in a sharded cluster architecture, you must create databases and collections to be sharded in the destination ApsaraDB for MongoDB instance and configure sharding based on your business needs. For more information, see Configure sharding to maximize the performance of shards.
    Note After you configure sharding for a cluster, the migrated data will be distributed among different shards. This maximizes the performance of the sharded cluster.

Limits

Billing

Migration type Task configuration fee Internet traffic fee
Schema migration and full data migration Free of charge. Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Pricing.
Incremental data migration Charged. For more information, see Pricing.

Migration types

Migration type Description
Schema migration DTS migrates the schemas of the required objects from the source ApsaraDB for MongoDB instance to the destination ApsaraDB for MongoDB instance.
Note DTS supports schema migration for the following types of objects: database, collection, and index.
Full data migration DTS migrates historical data of the required objects from the source ApsaraDB for MongoDB instance to the destination ApsaraDB for MongoDB instance.
Note DTS supports full data migration for the following types of objects: database, collection, and index.
Incremental data migration After full data migration is complete, DTS migrates incremental data from the source ApsaraDB for MongoDB instance to the destination ApsaraDB for MongoDB instance in real time.
Note DTS supports the following types of incremental updates:
  • CREATE DATABASE, CREATE COLLECTION, and CREATE INDEX
  • DROP DATABASE, DROP COLLECTION, and DROP INDEX
  • RENAME COLLECTION

Permissions required for database accounts

Database Schema migration 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 dbAdminAnyDatabase permission, the read and write permissions on the destination database, and the read permissions on the local database

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

Procedure

  1. Go to the .
    Note You can also log on to the Data Management (DMS) console. In the top navigation bar, choose DTS > Data Migration.
  2. In the upper-left corner of the page, select the region where the data migration instance resides.
    Select a region
  3. Click Create Task. On the page that appears, configure the source and destination databases.
    Warning After you select the source and destination instances, we recommend that you read the limits displayed at the top of the page. This ensures that you can create and run the data migration task.
    Section Parameter Description
    N/A Task Name

    DTS automatically generates a task name. We recommend that you specify an informative name to identify the task. You do not need to use a unique task name.

    Source Database Select Template
    If the connection settings of the instance has been saved as a template, you can select the connection name. DTS automatically applies the saved connection settings.
    Note
    • You can modify the connection settings of a template.
    • To edit the template name, you can click Edit Template Name at the bottom of the Source Database section.
    • The modified connection template will take effect the next time you select the connection template. The database instance that you have configured by using the template is not affected.
    Database Type Select MongoDB.
    Access Method Select Alibaba Cloud Instance.
    Instance Region Select the region where the source ApsaraDB for MongoDB instance resides.
    Instance ID Select the ID of the source ApsaraDB for MongoDB instance.
    Database Name Enter admin.
    Note You must enter the name of the authentication database. The database account is created in this database.
    Database Account Enter the database account of the source 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.

    Save as Template
    Click Save as Template. In the dialog box that appears, set the name of the database connection, and click OK. The connection settings of the database instance is saved as a template.
    Note We recommend that you specify an informative name to identify the database connection. You do not need to use a unique name.
    Destination Database Select Template
    If the connection settings of the instance has been saved as a template, you can select the connection name. DTS automatically applies the saved connection settings.
    Note
    • You can modify the connection settings of a template.
    • To edit the template name, you can click Edit Template Name at the bottom of the Source Database section.
    • The modified connection template will take effect the next time you select the connection template. The database instance that you have configured by using the template is not affected.
    Database Type Select MongoDB.
    Access Method Select Alibaba Cloud Instance.
    Instance Region Select the region where the destination ApsaraDB for MongoDB instance resides.
    Instance ID Select the ID of the destination ApsaraDB for MongoDB instance.
    Database Name Enter admin.
    Note You must enter the name of the authentication database. The database account is created in this database.
    Database Account Enter the database account of the destination 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.

    Save as Template
    Click Save as Template. In the dialog box that appears, set the name of the database connection, and click OK. The connection settings of the database instance is saved as a template.
    Note We recommend that you specify an informative name to identify the database connection. You do not need to use a unique name.
  4. In the lower part of the page, click Test Connectivity and Proceed.
  5. Select objects for the task and configure advanced settings.
    • Basic Settings
      Parameter Description
      Task Stages
      • To perform only full data migration, select Schema Migration and Full Data Migration.
      • To ensure service continuity during data migration, select Schema Migration, Full Data Migration, and Incremental Data Migration.
      Note If Incremental Data Migration is not selected, we recommend that you do not write data to the source instance during data migration. This ensures data consistency between the source and destination instances.

      For more information, see Migration types.

      Processing Mode of Conflicting Tables
      • Precheck and Report Errors: checks whether the destination database contains collections that have the same names as collections in the source database. If the source and destination databases do not contain identical collection names, the precheck is passed. Otherwise, an error is returned during precheck and the data migration task cannot be started.
        Note You can use the object name mapping feature to rename the collections that are migrated to the destination database. You can use this feature if the source and destination databases contain identical collection names and the collections in the destination database cannot be deleted or renamed. For more information, see Map object names.
      • Ignore Errors and Proceed: skips the precheck for identical collection names in the source and destination databases.
        Warning If you select Ignore Errors and Proceed, data consistency is not guaranteed and your business may be exposed to potential risks.
        • DTS does not migrate data records that have the same primary keys as data records in the destination database.
        • Data may fail to be initialized, only some columns are migrated, or the data migration task fails.
      Select Objects

      Select one or more objects from the Source Objects section and click the Rightwards arrow icon to move the objects to the Selected Objects section.

      Note You can select databases or collections as the objects to be migrated.
      Rename Databases and Tables
      • To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object.
      • To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time.
      Note If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be migrated.
      Filter data

      You can specify WHERE conditions to filter data. For more information, see Use SQL conditions to filter data.

    • Advanced Settings
      Parameter Description
      Set Alerts
      Specify whether to set alerts for the data migration task. If the task fails or the migration latency exceeds the threshold, the alert contacts will receive notifications.
      • Select No if you do not want to set alerts.
      • Select Yes to set alerts. In this case, you must also set the alert threshold and alert contacts.
      Capitalization of Object Names in Destination Instance

      Specify the capitalization of database names and collection names in the destination instance. By default, DTS default policy is selected. You can select other options to make sure that the capitalization of object names is consistent with that of the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.

      Retry Time for Failed Connections
      Specify the retry time for failed connections. Valid values: 10 to 1440. Unit: minutes. Default value: 120. We recommend that you set the retry time to more than 30 minutes. 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
      • If multiple DTS instances have the same source or destination database, the lowest value takes effect. For example, the retry time is set to 30 minutes for Instance A and 60 minutes for Instance B, DTS retries failed connections at an interval of 30 minutes.
      • 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.
  6. In the lower-right corner of the page, click Precheck.
    Note
    • Before you can start the data migration task, DTS performs a precheck. You can start the data migration task only after the task passes the precheck.
    • If the task fails to pass the precheck, you can click the Info icon icon next to each failed item to view details.
      • You can troubleshoot the issues based on the causes and run a precheck again.
      • If you do not need to troubleshoot the issues, you can ignore failed items and run a precheck again.
  7. Wait until the Success Rate becomes 100%. Then, click Next: Purchase Instance.
  8. On the Purchase Instance page, specify the Instance Class parameter for the data migration instance. The following table describes the parameter.
    Section Parameter Description
    Parameters Instance Class

    DTS provides several instance classes that have different performance in migration speed. You can select an instance class based on your business scenario. For more information, see Specifications of data migration instances.

  9. Read and select Data Transmission Service (Pay-as-you-go) Service Terms.
  10. Click Buy and Start to start the data migration task. You can view the progress of the task in the task list.