Data Transmission Service:Migrate data from a MongoDB Atlas database to an ApsaraDB for MongoDB instance

Usage notes

• DTS uses the resources of the source and destination databases during a full data migration. This may increase the loads on the database servers. If you migrate a large volume of data or if the server specifications do not 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 cannot migrate data from the admin or local database.

• The config database is an internal database. We recommend that you do not migrate data from this database.

• 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.

• The data is concurrently written to the destination database. Therefore, the storage space occupied in the destination database is 5% to 10% larger than the size of the data in the source database.

• Make sure that the destination ApsaraDB for MongoDB instance does not have the same primary key as that in the source instance. The default primary key is _id. Otherwise, data may be lost. If the destination instance has the same primary key as that in the source instance, delete the same document that corresponds to the _id primary key in the destination instance as that in the source instance without affecting your business.

Billing

Migration types

Permissions required for database accounts

For more information about how to create a database account and grant permissions to the database account, see the following topics:

• MongoDB Atlas database: db.createUser()

• ApsaraDB for MongoDB instance: Manage the permissions of MongoDB database users

Before you begin

1. Log on to the MongoDB Atlas console.

2. In the left-side navigation pane, click Network Access.

3. On the IP Whitelist tab of the Network Access page, click ADD IP ADDRESS.

4. Add the IP address of DTS corresponding to the region where the source MongoDB Atlas database resides to the security rule. For more information, see Add IP Access List Entries and Add the CIDR blocks of DTS servers to the security settings of on-premises databases.

   Note

   Perform this step to allow DTS to access your MongoDB Atlas database. Delete the security rule after the migration is complete.

Procedure (in the new DTS console)

1. Go to the Data Migration Tasks page.
   1. Log on to the Data Management (DMS) console.
   2. In the top navigation bar, click DTS.
   3. In the left-side navigation pane, choose DTS (DTS) > Data Migration.
   Note

   • Operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode and Customize the layout and style of the DMS console.
   • You can also go to the Data Migration Tasks page of the new DTS console.
2. From the drop-down list next to Data Migration Tasks, select the region in which the data migration instance resides.
   Note If you use the new DTS console, you must select the region in which the data migration instance resides in the upper-left corner.

3. Click Create Task. On the page that appears, configure the source and destination instances.

   Warning

   After you configure the source and destination databases, we recommend that you read the limits that are displayed in the upper part of the page. Otherwise, the task may fail or data inconsistency may occur.

   Section	Parameter	Description
   N/A	Task Name	The name of the task. DTS automatically assigns a name to the task. We recommend that you specify a descriptive name that makes it easy to identify the task. You do not need to specify a unique task name.
   Source Database	Select an existing DMS database instance	The database instance that you want to use. You can choose whether to select an existing instance based on your business requirements. If you select an existing instance, DTS automatically populates the parameters for the database. If you do not select an existing instance, you must manually configure parameters for the database.
   	Database Type	The type of the source database. Select MongoDB.
   	Access Method	The access method of the source database. Select Public IP Address.
   	Instance Region	The region in which the MongoDB Atlas database resides. Note If the region in which the MongoDB Atlas database resides is not displayed in the drop-down list, select a region that is geographically closest to the MongoDB Atlas database.
   	Architecture	Select Replica Set.
   	Hostname or IP address	The endpoint of the PRIMARY node in the MongoDB Atlas database. Note You can obtain the endpoint in the MongoDB Atlas console.
   	Port Number	The service port number of the MongoDB Atlas database. Default value: 27017.
   	Authentication Database	The name of the authentication database. The database account is created in this database.
   	Database Account	The account of the MongoDB Atlas database. For information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account.
   	Encryption	Specifies whether to encrypt the connection. Select Mongo Atlas SSL.
   Destination Database	Select an existing DMS database instance	The database instance that you want to use. You can choose whether to select an existing instance based on your business requirements. If you select an existing instance, DTS automatically populates the parameters for the database. If you do not select an existing instance, you must manually configure parameters for the database.
   	Database Type	The type of the destination database. Select MongoDB.
   	Access Method	The access method of the destination database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the destination ApsaraDB for MongoDB instance resides.
   	Architecture	The architecture in which the destination instance is deployed. Select an architecture based on your business requirements. Valid values: Replica Set: You can deploy multiple types of nodes on a replica set instance to implement high availability and read/write splitting. For more information, see Replica set instances. Sharded Cluster: A sharded cluster instance consists of three types of components: mongos, shard, and Configserver nodes. You can customize the configurations and number of mongos and shard nodes. For more information, see Sharded cluster instances.
   	Instance ID	The ID of the destination ApsaraDB for MongoDB instance.
   	Authentication Database	The name of the authentication database. The database account is created in this database. Note If you want to use the root account, enter admin in the Database Name field.
   	Database Account	The database account of the ApsaraDB for MongoDB instance. For more information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account.

4. In the lower part of the page, click Test Connectivity and Proceed.

5. If an IP address whitelist is configured for your self-managed database, add the CIDR blocks of DTS servers to the IP address whitelist. Then, click Test Connectivity and Proceed.

   Warning

   If the public CIDR blocks of DTS servers are automatically or manually added to the IP address whitelist of a database instance or to the security group rules of an ECS instance, security risks may arise. Therefore, before you use DTS to migrate data, you must understand and acknowledge the potential risks and take preventive measures, including but not limited to the following measures: enhancing the security of your account and password, limiting the ports that are exposed, authenticating API calls, regularly checking the IP address whitelist or ECS security group rules and forbidding unauthorized CIDR blocks, and connecting the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

6. Configure the objects to be migrated and the advanced settings.

   Parameter	Description
   Migration Types	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 you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
   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 collections that have identical collection names, the precheck is passed. Otherwise, an error is returned during the precheck and the data synchronization task cannot be started. Note You can use the object name mapping feature to rename the collections that are synchronized 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 Rename an object to be synchronized. 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 inconsistency may occur, and your business may be exposed to potential risks. DTS does not synchronize data records that have the same primary key values as data records in the destination database. Data may fail to be initialized, only some columns are synchronized, or the data synchronization task fails.
   Capitalization of Object Names in Destination Instance	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 ensure that the capitalization of object names is consistent with the default capitalization of object names in the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.
   Source Objects	Select one or more objects from the Source Objects section. Click the icon and add the objects to the Selected Objects section. Note You can select databases or collections as the objects to be migrated.
   Selected Objects	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 depend on the object may fail to be migrated. To specify WHERE conditions to filter data, right-click an object in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see the Map the name of a single object section of the "Map object names" topic. You can filter data by using SQL conditions only during full data migration. The SQL conditions used to filter data must be in the following format: {"_id":{$lte:"user100844658590795****"}}

7. Click Next: Advanced Settings to configure advanced settings.

   • Data Verification Settings

     For more information about how to use the data verification feature, see Enable data verification.

   • Advanced Settings

     Parameter	Description
     Set Alerts	Specifies whether to configure alerting for the data migration task. If the task fails or the migration latency exceeds the specified threshold, the alert contacts will receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. If you select Yes, you must also specify the alert threshold and alert contacts. For more information, see Configure monitoring and alerting.
     Retry Time for Failed Connections	The retry time range for failed connections. If the source or destination database fails to be connected after the data migration task is started, DTS immediately retries a connection within the time range. Valid values: 10 to 1440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS reconnects to the source and destination databases within the specified time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you set different retry time ranges for multiple data migration tasks that have the same source or destination database, the shortest retry time range that is set takes precedence. When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business requirements. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.
     The wait time before a retry when other issues occur in the source and destination databases.	The retry time range for other issues. For example, if DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set the parameter to a value greater than 10. If the failed operations are successfully performed within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Important The value of the The wait time before a retry when other issues occur in the source and destination databases parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
     Enable Throttling for Full Data Migration	During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads on the database servers. You can specify whether to enable throttling for the full data migration task. If you select Yes, you can configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and BPS of Full Data Migration parameters based on your business requirements to relieve the load on the destination instance. Note You can configure this parameter only if you select Full Data Migration as the migration type.
     Enable Throttling for Incremental Data Migration	You can specify whether to enable throttling for the incremental data migration task. If you select Yes, you can configure the RPS of Incremental Data Migration and BPS of Incremental Data Migration parameters based on your business requirements to relieve the load on the destination instance. Note You can configure this parameter only if you select Incremental Data Migration as the migration type.
     Configure ETL	Specifies whether to configure the extract, transform, and load (ETL) feature. For more information, see What is ETL?. Valid values: Yes: configures the ETL feature. You can enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or synchronization task. No: does not configure the ETL feature.

8. In the lower part of the page, click Next: Save Task Settings and Precheck.

   You can move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters to view the parameters to be specified when you call the relevant API operation to configure the DTS task.

   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, click View Details next to each failed item. After you troubleshoot the issues based on the error message, you can run a precheck again.

   • If an alert is triggered for an item during the precheck:

     • If the alert item cannot be ignored, click View Details next to the failed item and troubleshoot the issues. Then, run a precheck again.

     • If the alert item can be ignored, click Confirm Alert Details. In the View Details dialog box, click Ignore. In the message that appears, click OK. Then, click Precheck Again to run a precheck again. If you ignore the alert item, data inconsistency may occur and your business may be exposed to potential risks.

9. Wait until the success rate becomes 100%. Then, click Next: Purchase Instance.

10. On the Purchase Instance page, configure the Instance Class parameter for the data migration instance. The following table describes the parameters.

    Section	Parameter	Description
    New Instance Class	Resource Group	The resource group to which the data migration instance belongs. Default value: default resource group. For more information, see What is Resource Management?
    	Instance Class	DTS provides instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Specifications of data migration instances.

11. Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.

12. Click Buy and Start to start the data migration task. You can view the progress of the task in the task list.

Procedure (in the old DTS console)

1. Purchase a data migration instance. For more information, see Purchase a DTS instance.

2. Log on to the DTS console.
   Note If you are redirected to the Data Management (DMS) console, you can click the icon in the lower-right corner to go to the previous version of the DTS console.

3. In the left-side navigation pane, click Data Migration.

4. In the upper part of the Migration Tasks page, select the region in which the ApsaraDB for MongoDB instance resides.

5. Find the data migration instance that you purchased and click Configure Migration Task.

6. Configure the source and destination databases.

   

   Section	Parameter	Description
   N/A	Task Name	The task name that DTS automatically generates. We recommend that you specify a descriptive name that makes it easy to identify the task. You do not need to specify a unique task name.
   Source Database	Instance Type	The instance type of the source database. Select User-Created Database with Public IP Address.
   	Instance Region	The region in which the source instance resides. If you select User-Created Database with Public IP Address as the instance type of the source database, you do not need to configure the Instance Region parameter.
   	Database Type	The type of the source database. Select MongoDB.
   	Hostname or IP Address	The endpoint of the PRIMARY node in the MongoDB Atlas database. The following animation shows how to obtain the endpoint in the MongoDB Atlas console.
   	Port Number	The service port number of the MongoDB Atlas database. Default value: 27017.
   	Database Name	The name of the authentication database. The database account is created in this database.
   	Database Account	The account of the MongoDB Atlas database. For more information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account. Note After you specify the information about the source database, you can click Test Connectivity next to Database Password to check whether the information is correct. If the information is correct, the Passed message is displayed. If the information is incorrect, the Failed message is displayed and you must click Check next to the Failed message to modify the information.
   	Encryption	Specifies whether to encrypt the connection. Select SSL-encrypted.
   Destination Database	Instance Type	The instance type of the destination database. Select MongoDB Instance.
   	Instance Region	The region in which the ApsaraDB for MongoDB instance resides.
   	MongoDB Instance ID	The ID of the ApsaraDB for MongoDB instance.
   	Database Name	The name of the authentication database. The database account is created in this database. Note If you want to use the root account, enter admin in the Database Name field.
   	Database Account	The database account of the ApsaraDB for MongoDB instance. For more information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account. Note After you specify the information about the destination database, you can click Test Connectivity next to Database Password to check whether the information is correct. If the information is correct, the Passed message appears. If the information is incorrect, the Failed message appears and you must click Check next to the Failed message to modify the information.

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

   If the source or destination database is an Alibaba Cloud database instance, such as an ApsaraDB RDS for MySQL or ApsaraDB for MongoDB instance, DTS automatically adds the CIDR blocks of DTS servers to the IP address whitelist of the instance. If the source or destination database is a self-managed database hosted on an Elastic Compute Service (ECS) instance, DTS automatically adds the CIDR blocks of DTS servers to the security group rules of the ECS instance, and you must make sure that the ECS instance can access the database. If the self-managed database is hosted on multiple ECS instances, you must manually add the CIDR blocks of DTS servers to the security group rules of each ECS instance. If the source or destination database is a self-managed database that is deployed in a data center or provided by a third-party cloud service provider, you must manually add the CIDR blocks of DTS servers to the IP address whitelist of the database to allow DTS to access the database. For more information, see Add the CIDR blocks of DTS servers to the security settings of on-premises databases.

   Warning If the CIDR blocks of DTS servers are automatically or manually added to the whitelist of the database or instance, or to the ECS security group rules, security risks may arise. Therefore, before you use DTS to migrate data, you must understand and acknowledge the potential risks and take preventive measures, including but not limited to the following measures: enhance the security of your username and password, limit the ports that are exposed, authenticate API calls, regularly check the whitelist or ECS security group rules and forbid unauthorized CIDR blocks, or connect the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

8. Select the migration types and the objects to be migrated.

   Setting	Description
   Select the migration types	To perform only full data migration, select Full Data Migration. To ensure service continuity during data migration, select Full Data Migration and Incremental Data Migration. Note If you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
   Select the objects to be migrated	Select one or more objects from the Available section and click the icon to move the objects to the Selected section. Note DTS cannot migrate data from the admin, local, or config database. A migration object can be a database, collection, or function. By default, the name of an object remains unchanged after migration. You can change the names of the objects in the destination instance by using the object name mapping feature. 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 a retry time range for a 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 a retry time range based on your needs. If DTS reconnects to the source and destination databases within the specified period of time, DTS resumes the data migration task. Otherwise, the migration task fails. Note When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business requirements. You can also release the DTS instance at the earliest opportunity after the source and destination instances are released.

9. 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 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.

10. After the task passes the precheck, click Next.

11. In the Confirm Settings dialog box, specify the Instance Class parameter and select the check box to agree to Data Transmission Service (Pay-As-You-Go) Service Terms.

12. Click Buy and Start to start the data migration task.

    • Full data migration

      We recommend that you do not manually stop the task during full data migration. Otherwise, the data migrated to the destination database may be incomplete. Wait until the full data migration task automatically stops.

    • Incremental data migration

      An incremental data migration task does not automatically stop. You must manually stop the task.

      Note

      We recommend that you select an appropriate time to manually stop the data migration task. For example, you can stop the task during off-peak hours or before you switch your workloads to the ApsaraDB for MongoDB instance.

      1. Wait until Incremental Data Migration and The data migration task is not delayed are displayed in the progress bar of the data migration task. Then, stop writing data to the source database for several minutes. The delay time of incremental data migration may be displayed in the progress bar.

      2. Wait until the state of Incremental Data Migration changes to The migration task is not delayed again. Then, manually stop the migration task.

13. Switch your workloads to the destination ApsaraDB for MongoDB instance.