Data Transmission Service:Migrate an RDS instance across Alibaba Cloud accounts

Preparations

Configure RAM authorization for the Alibaba Cloud account that owns the database instance. For more information, see How to configure RAM authorization for cross-account tasks.

Configure a cross-account migration instance

1. Log on to the console with the main Alibaba Cloud account that owns the destination ApsaraDB RDS for MySQL instance, and navigate to the migration tasks page.

   From the DTS console

   1. Log on to the Data Transmission Service (DTS) console.

   2. In the navigation pane on the left, click Data Migration.

   3. In the upper-left corner of the page, select the region where the migration instance is located.

   From the DMS console

   Note

   The actual operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode console and Customize the layout and style of the DMS console.

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

   2. In the top menu bar, choose Data + AI > Data Transmission (DTS) > Data Migration.

   3. To the right of Data Migration Tasks, select the region where the migration instance is located.

2. Click Create Task to navigate to the task configuration page.

3. Configure the source and destination databases.

   Category	Parameter	Description
   N/A	Task Name	DTS automatically generates a task name. We recommend that you specify a descriptive name for easy identification. The name does not need to be unique.
   Source Database	Select Existing Connection	To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured. Note In the DMS console, this parameter is named Select a DMS database instance.. If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.
   	Database Type	Select MySQL.
   	Connection Type	Select Alibaba Cloud Instance.
   	Instance Region	Select the region where the source ApsaraDB RDS for MySQL instance resides. Note The source and destination ApsaraDB RDS for MySQL instances can be in different regions.
   	Replicate Data Across Alibaba Cloud Accounts	Select Yes.
   	Alibaba Cloud Account	Enter the ID of the main Alibaba Cloud account that owns the source ApsaraDB RDS for MySQL instance. Note For instructions on how to obtain the ID, see Obtain the ID of the main Alibaba Cloud account to which the source database belongs.
   	RAM Role Name	Enter the name of the RAM role created in the main Alibaba Cloud account that owns the source ApsaraDB RDS for MySQL instance, for example, ram-for-dts. Note Do not enter a RAM user name, the Alibaba Resource Name (ARN) of the RAM role, or the default DTS role AliyunDTSDefaultRole. For creation instructions, see Step 1: Create a RAM role.
   	RDS Instance ID	Select the instance ID of the source ApsaraDB RDS for MySQL instance. Note If an alert appears when you select the RDS instance ID, modify the configuration as prompted. For common alerts, see Common errors.
   	Database Account	Enter the username of the source MySQL database. For permission requirements, see Required permissions for database accounts.
   	Database Password	Enter the password for the database account.
   	Encryption	Select Non-encrypted or SSL-encrypted as needed. In this example, select Non-encrypted. Note If you select SSL-encrypted, you must first enable SSL encryption for the RDS instance. For more information, see Configure SSL encryption.
   Destination Database	Select Existing Connection	To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured. Note In the DMS console, this parameter is named Select a DMS database instance.. If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.
   	Database Type	Select MySQL.
   	Connection Type	Select Alibaba Cloud Instance.
   	Instance Region	Select the region where the destination ApsaraDB RDS for MySQL instance resides. Note The source and destination ApsaraDB RDS for MySQL instances can be in different regions.
   	Replicate Data Across Alibaba Cloud Accounts	In this example, select No.
   	RDS Instance ID	Select the instance ID of the destination ApsaraDB RDS for MySQL instance.
   	Database Account	Enter the username of the destination MySQL database. For permission requirements, see Required permissions for database accounts.
   	Database Password	Enter the password for the database account.
   	Encryption	Select Non-encrypted or SSL-encrypted as needed. In this example, select Non-encrypted. Note If you select SSL-encrypted, you must first enable SSL encryption for the RDS instance. For more information, see Configure SSL encryption.

4. After you complete the configuration, click Test Connectivity and Proceed at the bottom of the page.

   Note

   • Ensure that the IP address segment of the DTS service is automatically or manually added to the security settings of the source and destination databases to allow access from DTS servers. For more information, see Add DTS server IP addresses to a whitelist.

   • If the source or destination database is a self-managed database (the Access Method is not Alibaba Cloud Instance), you must also click Test Connectivity in the CIDR Blocks of DTS Servers dialog box that appears.

5. Configure the task objects.

   1. On the Configure Objects page, configure the objects that you want to migrate.

      Parameter	Description
      Migration Types	If you only need to perform a full migration, select both Schema Migration and Full Data Migration. To perform a migration with no downtime, select Schema Migration, Full Data Migration, and Incremental Data Migration. Note If you do not select Schema Migration, you must ensure that a database and tables to receive the data exist in the destination database. You can also use the object name mapping feature in the Selected Objects box as needed. If you do not select Incremental Data Migration, do not write new data to the source instance during data migration to ensure data consistency.
      Method to Migrate Triggers in Source Database	Select a method to migrate triggers. If the objects to be migrated do not involve triggers, you can skip this configuration. For more information, see Configure a method to migrate triggers. Note This parameter can be configured only when both Schema Migration and Incremental Data Migration are selected for Migration Types.
      Enable Migration Assessment	This assessment checks whether the source and destination schemas (such as index length, stored procedures, and dependent tables) meet requirements. Select Yes or No. Note You can configure this parameter only when Schema Migration is selected for Migration Types. If you select Yes, the precheck may take longer. You can view the Assessment Result during the precheck phase. The assessment results do not affect the precheck result.
      Processing Mode of Conflicting Tables	Precheck and Report Errors: Checks whether tables with the same names exist in the destination database. If no tables with the same names exist, the precheck is passed. If tables with the same names exist, an error is reported during the precheck, and the data migration task does not start. Note If a table in the destination database has the same name but cannot be easily deleted or renamed, you can change the name of the table in the destination database. For more information, see Object name mapping. Ignore Errors and Proceed: Skips the check for tables with the same names. Warning Selecting Ignore Errors and Proceed may cause data inconsistency and business risks. For example: If the table schemas are consistent and a record in the destination database has the same primary key value as a record in the source database: During full migration, DTS keeps the record in the destination database. The record from the source database is not migrated. During incremental migration, DTS does not keep the record in the destination database. The record from the source database overwrites the record in the destination database. If the table schemas are inconsistent, only some columns of data may be migrated, or the migration may fail. Proceed with caution.
      Whether to migrate Event	Choose whether to migrate events from the source database. If you select Yes, additional steps are required as described in Synchronize or migrate events.
      Capitalization of Object Names in Destination Instance	You can configure the case sensitivity policy for the names of migrated objects, such as databases, tables, and columns, in the destination instance. By default, DTS default policy is selected. You can also choose to keep the case sensitivity consistent with the default policy of the source or destination database. For more information, see Case sensitivity of object names in the destination database.
      Source Objects	In the Source Objects box, click the objects to migrate, and then click to move them to the Selected Objects box. Note The granularity for selecting migration objects is database, table, and column. If you select only tables or columns as migration objects, other objects such as views, triggers, and stored procedures are not migrated to the destination database.
      Selected Objects	To set the name of a migration object in the destination instance, or to specify the object that receives data in the destination instance, right-click the migration object in the Selected Objects box to make changes. For more information, see Object name mapping. To remove a selected migration object, click the object in the Selected Objects box, and then click to move it to the Source Objects box. Note If you use the object name mapping feature, other objects that depend on the mapped object may fail to migrate. To set a WHERE clause to filter data, right-click the table to migrate in the Selected Objects box and set the filter condition in the dialog box that appears. For more information about how to set the condition, see Set filter conditions. To select the SQL operations for incremental migration, right-click the migration object in the Selected Objects box and select the desired SQL operations in the dialog box that appears.

   2. Click Next: Advanced Settings to configure advanced parameters.

      Parameter	Description
      Dedicated Cluster for Task Scheduling	By default, DTS schedules tasks on a shared cluster. You do not need to select one. If you want more stable tasks, you can purchase a dedicated cluster to run DTS migration tasks.
      Copy the temporary table of the Online DDL tool that is generated in the source table to the destination database.	If you use Data Management (DMS) or gh-ost to perform online DDL changes in the source database, you can choose whether to migrate the data from the temporary tables generated by the online DDL changes. Important DTS tasks do not support using tools such as pt-online-schema-change to perform online DDL changes. Otherwise, the DTS task fails. The processing methods for each phase are as follows: The Schema Migration and Full Data Migration phases do not allow DDL operations that change the database or table structure. Therefore, they are not controlled by the online DDL policy. Schema Migration: Not controlled by the online DDL policy. Related temporary tables are created. Full Data Migration: Not controlled by the online DDL policy. The migration of temporary tables is not included in the full migration objects. All tables whose names match the regular expression (^_(.+)_(?:gho|new)$ or ^_(.+)_(?:ghc|del|old)$) are filtered out. Incremental Data Migration: Controlled by the online DDL policy. Yes: Migrates data changes from temporary tables (for example, _table_name_gho) generated by online DDL operations. No, Adapt to DMS Online DDL and No, Adapt to gh-ost: Filters out data changes from temporary tables (for example, _table_name_gho) generated by tools such as gh-ost based on regular expression rules. Yes: Migrates the data from the temporary tables generated by online DDL changes. Note If online DDL changes generate a large amount of data in temporary tables, it may cause task latency. No, Adapt to DMS Online DDL: Does not migrate the data from the temporary tables generated by online DDL changes. It only migrates the original DDL statements executed using Data Management (DMS). Note This option causes tables in the destination database to be locked. No, Adapt to gh-ost: Does not migrate the data from the temporary tables generated by online DDL changes. It supports custom filtering rules. DTS filters out data changes from temporary tables (for example, _table_name_gho) generated by tools such as gh-ost based on regular expression rules. You can modify the default regular expressions used to match shadow and useless tables as needed: Shadow table: ^_(.+)_(?:gho|new)$ Useless table: ^_(.+)_(?:ghc|del|old)$ Note This option causes tables in the destination database to be locked.
      Whether to Migrate Accounts	Choose whether to migrate the account information from the source database. If you select Yes, you also need to select the accounts to be migrated and confirm their permissions.
      Retry Time for Failed Connections	After the migration task starts, if the connection to the source or destination database fails, DTS reports an error and immediately begins to retry the connection. The default retry duration is 720 minutes. You can customize the retry time to a value from 10 to 1440 minutes. We recommend that you set the duration to more than 30 minutes. If DTS reconnects to the source and destination databases within the specified duration, the migration task automatically resumes. Otherwise, the task fails. Note For multiple DTS instances that share the same source or destination, the network retry time is determined by the setting of the last created task. Because you are charged for the task during the connection retry period, we recommend that you customize the retry time based on your business needs, or release the DTS instance as soon as possible after the source and destination database instances are released.
      Retry Time for Other Issues	After the migration task starts, if a non-connectivity issue, such as a DDL or DML execution exception, occurs in the source or destination database, DTS reports an error and immediately begins to retry the operation. The default retry duration is 10 minutes. You can customize the retry time to a value from 1 to 1440 minutes. We recommend that you set the duration to more than 10 minutes. If the related operations succeed within the specified retry duration, the migration task automatically resumes. Otherwise, the task fails. Important The value of Retry Time for Other Issues must be less than the value of Retry Time for Failed Connections.
      Enable Throttling for Full Data Migration	During full migration, DTS consumes read and write resources on the source and destination databases, which may increase the database load. If required, you can enable throttling for the full migration task. You can set Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) to reduce the load on the destination database. Note This configuration item is available only if you select Full Data Migration for Migration Types. You can also adjust the full migration speed after the migration instance is running.
      Enable Throttling for Incremental Data Migration	If required, you can also choose to set speed limits for the incremental migration task. You can set RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) to reduce the load on the destination database. Note This configuration item is available only if you select Incremental Data Migration for Migration Types. You can also adjust the incremental migration speed after the migration instance is running.
      Whether to delete SQL operations on heartbeat tables of forward and reverse tasks	Choose whether DTS writes heartbeat SQL information to the source database while the instance is running. Yes: Does not write heartbeat SQL information to the source database. The DTS instance may display latency. No: Writes heartbeat SQL information to the source database. This may interfere with source database operations like physical backups and cloning.
      Environment Tag	You can select an environment tag to identify the instance. In this example, no selection is needed.
      Configure ETL	Choose whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: Enables the ETL feature. Enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: Disables the ETL feature.
      Monitoring and Alerting	Select whether to set alerts and receive alert notifications based on your business needs. No: Does not set an alert. Yes: Configure alerts by setting an alert threshold and an alert notifications. If a migration fails or the latency exceeds the threshold, the system sends an alert notification.

   3. Click Next: Data Validation to configure a data validation task.

      For more information about the data validation feature, see Configure data validation.

6. Save the task and run a precheck.

   • To view the parameters for configuring this instance when you call the API operation, move the pointer over the Next: Save Task Settings and Precheck button and click Preview OpenAPI parameters in the bubble that appears.

   • If you do not need to view or have finished viewing the API parameters, click Next: Save Task Settings and Precheck at the bottom of the page.

   Note

   • Before the migration task starts, DTS performs a precheck. The task starts only after it passes the precheck.

   • If the precheck fails, click View Details next to the failed check item, fix the issue based on the prompt, and then run the precheck again.

   • If a warning is reported during the precheck:

     • For check items that cannot be ignored, click View Details next to the failed item, fix the issue based on the prompt, and then run the precheck again.

     • For check items that can be ignored, you can click Confirm Alert Details, Ignore, OK, and Precheck Again to skip the alert item and run the precheck again. If you choose to ignore a warning, it may cause issues such as data inconsistency and pose risks to your business.

7. Purchase the instance.

   1. When the Success Rate is 100%, click Next: Purchase Instance.

   2. On the Purchase page, select the link specification for the data migration instance. For more information, see the following table.

      Category	Parameter	Description
      New Instance Class	Resource Group Settings	Select the resource group to which the instance belongs. The default value is default resource group. For more information, see What is Resource Management?
      	Instance Class	DTS provides migration specifications with different performance levels. The link specification affects the migration speed. You can select a specification based on your business scenario. For more information, see Data migration link specifications.

   3. After the configuration is complete, read and select Data Transmission Service (Pay-as-you-go) Service Terms.

   4. Click Buy and Start. In the OK dialog box that appears, click OK.

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

      Note

      • If the migration task does not include incremental migration, it stops automatically after the full migration is complete. After the task stops, its Status changes to Completed.

      • If the migration task includes incremental migration, it does not stop automatically. The incremental migration task continues to run. While the incremental migration task is running, the Status of the task is Running.