Data Transmission Service：Migrate data from an ApsaraDB for MongoDB standalone instance to another ApsaraDB for MongoDB instance

Supported source and destination databases

Prerequisites

• The source ApsaraDB for MongoDB instance of the standalone architecture and the destination ApsaraDB for MongoDB instance are created. The destination ApsaraDB for MongoDB instance can be deployed in any available architecture. For more information, see Create a standalone instance, Create a replica set instance, and Create a sharded cluster instance.

  Note

  For more information about the supported database versions, see Overview of data migration scenarios.

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

• If the destination ApsaraDB for MongoDB instance is deployed in a sharded cluster architecture, you need to create databases and collections to be sharded in the destination ApsaraDB for MongoDB instance and configure sharding based on your business requirements. 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.

Usage notes

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 for an ApsaraDB for MongoDB instance, see Manage user permissions on MongoDB databases.

Procedure

1. Go to the Data Migration Tasks page.

   1. Log on to the Data Management (DMS) console.

   2. In the top navigation bar, move the pointer over DTS.

   3. Choose DTS (DTS) > Data Migration.

   Note

   • The actual 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 page of the new DTS console.

2. From the drop-down list on the right side of Data Migration Tasks, select the region in which your 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 Create Data Migration Task page, configure the source and destination databases. The following table describes the parameters.

   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 generates a task name. We recommend that you specify an informative name 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 use 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 configure the following database information.
   	Database Type	The type of the source database. Select MongoDB.
   	Access Method	The access method of the source database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the source ApsaraDB for MongoDB instance resides.
   	Architecture	The architecture in which the source instance is deployed. Select Replica Set for an ApsaraDB for MongoDB standalone instance. Replica Set: You can deploy multiple types of nodes on a replica set instance to achieve 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 source ApsaraDB for MongoDB instance.
   	Authentication Database	The name of the authentication database to which the objects to be migrated in the source ApsaraDB for MongoDB instance belong. If you did not change the name before, the default value is admin.
   	Database Account	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	The password that is used to access the database instance.
   Destination Database	Select an existing DMS database instance	The database instance that you want to use. You can choose whether to use 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 configure the following database information.
   	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 achieve 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 config server 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 to which the objects to be migrated in the destination ApsaraDB for MongoDB instance belong. If you did not change the name before, the default value is admin.
   	Database Account	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	The password that is used to access the database instance.

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

   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 the CIDR blocks of DTS servers section of the Add the CIDR blocks of DTS servers topic.

   Warning

   If the public CIDR blocks of DTS servers are automatically or manually added to the 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 username and password, limiting the ports that are exposed, authenticating API calls, regularly checking the whitelist or security group rules and forbidding unauthorized CIDR blocks, or connecting the database instance to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

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

   Parameter	Description
   Migration Types	Select Schema Migration and Full Data Migration. Note In this scenario, DTS does not support incremental data migration. To ensure data consistency, we recommend that you do not write data to the source database during data migration. 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 the 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 inconsistency may occur, 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.
   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.
   Source Objects	Select one or more objects from the Available section. Click the icon and add the objects to the Selected 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 are dependent 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 Specify filter conditions.

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

   Parameter	Description
   Monitoring and Alerting	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 receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see the Configure monitoring and alerting when you create a DTS task section of the Configure monitoring and alerting topic.
   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 retry 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 is reconnected to the source and destination databases within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you specify different retry time ranges for multiple data migration tasks that share the same source or destination database, the value that is specified later 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 the earliest opportunity after the source database and destination instance are released.
   Configure ETL	Select Yes or No based on your business requirements. If you select Yes, you must enter domain-specific language (DSL) statements in the code editor. For more information, see Configure ETL in a data migration or synchronization task.

7. 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 analyze the causes based on the check results, troubleshoot the issues. Then, run a precheck again.

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

     • If an 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.

8. Wait until Success Rate becomes 100%. Then, click Next: Purchase Instance.

9. 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 Instance classes of data migration instances.

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

11. Click Buy and Start. In the message that appears, click OK.

    You can view the progress of the task on the Data Migration page.