Data Transmission Service:Migrate data from an Amazon RDS for Oracle instance to an ApsaraDB RDS for MySQL instance

Limits

• DTS uses read and write resources of the source and destination databases during full data migration. This may increase the loads of the database servers. If the database performance is unfavorable, the specification is low, or the data volume is large, database services may become unavailable. For example, DTS occupies a large amount of read and write resources in the following cases: a large number of slow SQL queries are performed on the source database, the tables have no primary keys, or a deadlock occurs in the destination database. 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. For example, you can migrate data when the CPU utilization of the source and destination databases is less than 30%.
• The tables to be migrated in the source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.
• DTS uses the ROUND(COLUMN,PRECISION) function to retrieve values from columns of the FLOAT or DOUBLE data type. If you do not specify a precision, DTS sets the precision for the FLOAT data type to 38 digits and the precision for the DOUBLE data type to 308 digits. You must check whether the precision settings meet your business requirements.
• DTS automatically creates a destination database in the ApsaraDB RDS for MySQL instance. However, if the name of the source database is invalid, you must manually create a database in the ApsaraDB RDS for MySQL instance before you configure the data migration task.
  Note For more information about the database naming conventions of ApsaraDB RDS for MySQL databases and how to create a database, see Create a database for an ApsaraDB RDS for MySQL instance.
• If a data migration task fails, DTS automatically resumes the task. Before you switch your workloads to the destination instance, stop or release the data migration task. Otherwise, the data in the source database overwrites the data in the destination instance after the task is resumed.

Billing

Migration types

• Schema migration

  DTS supports schema migration for the following types of objects: table, index, constraint, and sequence. DTS does not support schema migration for the following types of objects: view, synonym, trigger, stored procedure, function, package, and user-defined type.

• Full data migration

  DTS migrates historical data of the required objects from the source database in the Amazon RDS for Oracle instance to the destination database in the ApsaraDB RDS for MySQL instance.

• Incremental data migration

  DTS retrieves redo log files from the source database in the Amazon RDS for Oracle instance. Then, DTS synchronizes incremental data from the source database in the Amazon RDS for Oracle instance to the destination database in the ApsaraDB RDS for MySQL instance. Incremental data migration allows data to be migrated smoothly without interrupting the services of self-managed applications when you migrate data from an Oracle database.

SQL operations that can be synchronized during incremental data migration

• INSERT, DELETE, and UPDATE

• CREATE TABLE

  Note

  If a CREATE TABLE operation creates a partitioned table or a table that contains functions, DTS does not synchronize the operation.

• ALTER TABLE, including only ADD COLUMN, DROP COLUMN, RENAME COLUMN, and ADD INDEX

• DROP TABLE

• RENAME TABLE, TRUNCATE TABLE, and CREATE INDEX

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:

• Amazon RDS for Oracle instance: CREATE USER and GRANT

• ApsaraDB RDS for MySQL instance: Create databases and accounts for an ApsaraDB RDS for MySQL instance

Data type mappings

For more information, see Data type mappings between heterogeneous databases.

Before you begin

1. Log on to the Amazon RDS Management Console.

2. Go to the basic information page of the Amazon RDS for Oracle instance.

3. In the Security group rules section, click the name of the security group to which the existing inbound rule belongs.

   

4. On the Security Groups page, click the Inbound tab in the Security Group section. On the Inbound tab, click Edit. In the Edit inbound rules dialog box, add the CIDR blocks of DTS servers that reside in the corresponding region to the inbound rule. For more information, see Add the CIDR blocks of DTS servers to the security settings of on-premises databases.

   

   Note

   • You need to add only the CIDR blocks of DTS servers that reside in the same region as the destination database. For example, the source database resides in the Singapore region and the destination database resides in the China (Hangzhou) region. You need to add only the CIDR blocks of DTS servers that reside in the China (Hangzhou) region.

   • You can add all of the required CIDR blocks to the inbound rule at a time.

5. Modify the log settings of the Amazon RDS for Oracle instance. Skip this step if you do not need to perform incremental data migration.

   • If the database version of the Amazon RDS for Oracle instance is 12c or later (non-multitenant architecture), perform the following steps to configure the log settings:

     1. Use the master user account and the SQL*Plus tool to connect to the Amazon RDS for Oracle instance.

     2. Enable archive logging and supplemental logging.

        Type	Procedure
        Archive logging	Execute the following statement to check whether archive logging is enabled: SELECT LOG_MODE FROM v$database; View and set the retention period for archived logs. Note We recommend that you set the retention period of archived logs to at least 72 hours. In this example, the retention period is set to 72 hours. exec rdsadmin.rdsadmin_util.show_configuration; exec rdsadmin.rdsadmin_util.set_configuration('archivelog retention hours', 72);
        Supplemental logging	Enable supplemental logging at the database or table level: Enable database-level supplemental logging Execute the following statement to check whether database-level supplemental logging is enabled: SELECT supplemental_log_data_min, supplemental_log_data_pk, supplemental_log_data_ui FROM v$database; Enable primary key and unique key supplemental logging at the database level: exec rdsadmin.rdsadmin_util.alter_supplemental_logging('ADD', 'PRIMARY KEY'); exec rdsadmin.rdsadmin_util.alter_supplemental_logging('ADD', 'UNIQUE'); Enable table-level supplemental logging by using one of the following methods: Enable table-level supplemental logging for all columns: exec rdsadmin.rdsadmin_util.alter_supplemental_logging('ADD', 'ALL'); Enable primary key supplemental logging at the table level: exec rdsadmin.rdsadmin_util.alter_supplemental_logging('ADD', 'PRIMARY KEY');

     3. Grant fine-grained permissions to the database account of the Amazon RDS for Oracle instance.

        Grant fine-grained permissions

        Webpack

        # Create a database account and grant permissions to the account. In this example, a database account named RDSDT_DTSACCT is created.
        create user RDSDT_DTSACCT IDENTIFIED BY RDSDT_DTSACCT;
        grant create session to RDSDT_DTSACCT;
        grant connect to RDSDT_DTSACCT;
        grant resource to RDSDT_DTSACCT;
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$LOGMNR_LOGS','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('ALL_OBJECTS','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('ALL_TAB_COLS','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('DBA_REGISTRY','RDSDT_DTSACCT','SELECT');
        grant select any table to RDSDT_DTSACCT;
        grant select any transaction to RDSDT_DTSACCT;
        -- v$log privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$LOG','RDSDT_DTSACCT','SELECT');
        -- v$logfile privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$LOGFILE','RDSDT_DTSACCT','SELECT');
        -- v$archived_log privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$ARCHIVED_LOG','RDSDT_DTSACCT','SELECT');
        -- v$parameter privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$PARAMETER','RDSDT_DTSACCT','SELECT');
        -- v$database privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$DATABASE','RDSDT_DTSACCT','SELECT');
        -- v$active_instances privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$ACTIVE_INSTANCES','RDSDT_DTSACCT','SELECT');
        -- v$instance privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$INSTANCE','RDSDT_DTSACCT','SELECT');
        -- v$logmnr_contents privileges
        exec rdsadmin.rdsadmin_util.grant_sys_object('V_$LOGMNR_CONTENTS','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('USER$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('OBJ$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('COL$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('IND$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('ICOL$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('CDEF$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('CCOL$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('TABPART$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('TABSUBPART$','RDSDT_DTSACCT','SELECT');
        exec rdsadmin.rdsadmin_util.grant_sys_object('TABCOMPART$','RDSDT_DTSACCT','SELECT');
        grant LOGMINING TO RDSDT_DTSACCT;
        grant EXECUTE_CATALOG_ROLE to RDSDT_DTSACCT;
        exec rdsadmin.rdsadmin_util.grant_sys_object('DBMS_LOGMNR','RDSDT_DTSACCT','EXECUTE');
        grant select on v$database to rdsdt_dtsacct;
        grant select on dba_objects to rdsdt_dtsacct;
        grant select on DBA_TAB_COMMENTS to rdsdt_dtsacct;
        grant select on dba_tab_cols to rdsdt_dtsacct;
        grant select_catalog_role TO rdsdt_dtsacct;

   • If the database version of the Amazon RDS for Oracle instance is 9i, 10g, or 11g, perform the following steps to configure the log settings:

     1. Use the master user account and the SQL*Plus tool to connect to the Amazon RDS for Oracle instance.

     2. Run the archive log list; command to check whether the Amazon RDS for Oracle instance is running in ARCHIVELOG mode.

        Note

        If the instance is running in NOARCHIVELOG mode, switch the mode to ARCHIVELOG. For more information, see Managing Archived Redo Logs.

     3. Enable force logging.

        exec rdsadmin.rdsadmin_util.force_logging(p_enable => true);

     4. Enable supplemental logging for primary keys.

        begin rdsadmin.rdsadmin_util.alter_supplemental_logging(p_action => 'ADD',p_type => 'PRIMARY KEY');end;/

     5. Enable supplemental logging for unique keys.

        begin rdsadmin.rdsadmin_util.alter_supplemental_logging(p_action => 'ADD',p_type => 'UNIQUE');end;/

     6. Set a retention period for archived logs.

        begin rdsadmin.rdsadmin_util.set_configuration(name => 'archivelog retention hours', value => '24');end;/

     7. Set a retention period for archived logs.

        Note

        We recommend that you set the retention period of archived logs to at least 24 hours.

     8. Commit the changes.

        commit;

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 Configure the DMS console based on your business requirements.
   • 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 Create Task wizard page, configure the source and destination databases.

   Warning After you configure the source and destination databases, we recommend that you read the limits displayed at the top of the page. Otherwise, the task may fail or data inconsistency may occur.

   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	Database Type	The type of the source database. Select Oracle.
   	Access Method	The access method of the source database. Select Public IP Address.
   	Instance Region	The region in which the Amazon RDS for Oracle instance resides. Note If the region in which the Amazon RDS for Oracle instance resides is not displayed in the drop-down list, select a region that is geographically closest to the Amazon RDS for Oracle instance.
   	Hostname or IP Address	The endpoint that is used to access the Amazon RDS for Oracle instance. Note You can obtain the endpoint on the basic information page of the Amazon RDS for Oracle instance.
   	Port Number	The service port number of the Amazon RDS for Oracle instance. Default value: 1521.
   	Oracle Type	The architecture of the source database. If you select Non-RAC Instance, you must configure the SID parameter. If you select RAC or PDB Instance, you must configure the Service Name parameter. In this example, Non-RAC Instance is selected.
   	Database Account	The database account of the Amazon RDS for Oracle instance. 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.
   Destination Database	Database Type	The type of the destination database. Select MySQL.
   	Access Method	The access method of the destination database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the destination ApsaraDB RDS for MySQL instance resides.
   	RDS instance ID	The ID of the destination ApsaraDB RDS for MySQL instance.
   	Database Account	The database account of the ApsaraDB RDS for MySQL instance. 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 to the source database. Select Non-encrypted or SSL-encrypted based on your business requirements. If you select SSL-encrypted, you must enable SSL encryption for the ApsaraDB RDS for MySQL instance before you configure the data migration task. For more information, see Configure SSL encryption for an ApsaraDB RDS for MySQL instance.

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, you must add the CIDR blocks of DTS servers to the IP address whitelist. Then, click Test Connectivity and Proceed.
   Warning If the CIDR blocks of DTS servers are automatically or manually added to the IP address whitelist of the database instance or 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 account and password, limit the ports that are exposed, authenticate API calls, regularly check the IP address whitelist or ECS security group rules and forbid unauthorized CIDR blocks, and connect the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

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

   Parameter	Description
   Migration Type	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 tables that have the same names as tables in the source database. If the source and destination databases do not contain tables that have the same 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 tables that are migrated to the destination database. You can use this feature if the source and destination databases contain tables that have identical names and the tables 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 table 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. If the source and destination databases have the same schema, DTS does not migrate data records that have the same primary keys as data records in the destination database. If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
   Source Objects	Select one or more objects from the Source Objects section and click the icon to add the objects to the Selected Objects section. Note You can select columns, tables, or databases 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 a table in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see Use SQL conditions to filter data. To migrate the SQL operations performed on a specific database or table, right-click the object in the Selected Objects section. In the dialog box that appears, select the SQL operations that you want to migrate. For more information about the SQL statements that can be synchronized, see the SQL operations that can be synchronized during incremental data migration section of this topic.

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
     Select the dedicated cluster used to schedule the task	By default, DTS schedules the task to a shared cluster. You do not need to configure this parameter. You can purchase a dedicated cluster of the specified specifications to run data migration tasks. For more information, see What is a DTS dedicated cluster?
     Set Alerts	Specifies 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. Valid values: No: does not set alerts. Yes: sets alerts. If you select Yes, you must also set the alert threshold and alert contacts. For more information,see Configure monitoring and alerting when you create a DTS task.
     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 the DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the 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 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 Query Rate on 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 when you select Full Data Migration as a 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 when you select Incremental Data Migration as a 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 data 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 causes, 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 an 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 value becomes 100%. Then, click Next: Purchase Instance.
10. On the Purchase Instance page, specify the Instance Class parameter for the data migration instance. The following table describes the parameter.

    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 various 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 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. You can view the progress of the task in the task list.

Procedure (in the old DTS console)

1. 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.
2. In the left-side navigation pane, click Data Migration.
3. At the top of the Migration Tasks page, select the region where the destination cluster resides.
4. In the upper-right corner of the page, click Create Migration Task.

5. 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 Oracle.
   	Hostname or IP Address	The endpoint that is used to access the Amazon RDS for Oracle instance. Note You can obtain the endpoint on the basic information page of the Amazon RDS for Oracle instance.
   	Port Number	The service port number of the Amazon RDS for Oracle instance. Default value: 1521.
   	Instance Type	If you select Non-RAC Instance, you must configure the SID parameter. If you select RAC Instance, you must configure the Service Name parameter. In this example, Non-RAC Instance is selected. Then, configure the SID parameter.
   	Database Account	The database account of the Amazon RDS for Oracle instance. 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. Note After you specify the source database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message is displayed. If the Failed message is displayed, click Check next to Failed to modify the source database parameters based on the check results.
   Destination Database	Instance Type	The instance type of the destination database. Select RDS Instance.
   	Instance Region	The region in which the ApsaraDB RDS for MySQL instance resides.
   	RDS Instance ID	The ID of the ApsaraDB RDS for MySQL instance.
   	Database Account	The database account of the ApsaraDB RDS for MySQL instance. 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. Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message is displayed. If the Failed message is displayed, click Check next to Failed to modify the destination database parameters based on the check results.

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

   If the source or destination database instance is an Alibaba Cloud database instance, such as an ApsaraDB RDS for MySQL or ApsaraDB for MongoDB instance, or is a self-managed database hosted on Elastic Compute Service (ECS), DTS automatically adds the CIDR blocks of DTS servers to the whitelist of the database instance or ECS security group rules. If the source or destination database is a self-managed database on data centers or is from other cloud service providers, you must manually add the CIDR blocks of DTS servers to allow DTS to access the database. For more information about the CIDR blocks of DTS servers, see the "CIDR blocks of DTS servers" section of the Add the CIDR blocks of DTS servers to the security settings of on-premises databases topic.

   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.

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

   

   Setting	Description
   Select the 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 Incremental Data Migration is not selected, 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 You can select columns, tables, or databases as the objects to be migrated. By default, after an object is migrated to the destination database, the name of the object remains unchanged in the destination database. You can use the object name mapping feature to rename the objects that are migrated to the ApsaraDB RDS for MySQL instance. For more information, see Object name mapping. If you use the object name mapping feature to rename an object, other objects that depend on the object may fail to be migrated.
   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 the 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 the retry time range based on your business requirements. If DTS reconnects 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 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.

8. 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.
9. After the task passes the precheck, click Next.
10. In the Confirm Settings dialog box, specify the Channel Specification parameter and select Data Transmission Service (Pay-As-You-Go) Service Terms.
11. Click Buy and Start to start the data migration task.
    • Schema migration and 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. You can wait until the data migration task automatically stops.

    • Schema migration, full data migration, and incremental data migration

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

      Important 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 destination cluster.
      1. 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 latency of incremental data migration may be displayed in the progress bar.
      2. Wait until the status of incremental data migration changes to The migration task is not delayed again. Then, manually stop the migration task.

12. Switch your workloads to the ApsaraDB RDS for MySQL instance.