You can migrate databases from Elastic Compute Service (ECS) instances to ApsaraDB RDS instances that run RDS High-availability Edition to ensure high availability, reliability, security, and convenience of database services. This topic describes how to migrate a self-managed database on an ECS instance to an ApsaraDB RDS instance that runs RDS High-availability Edition by using Data Transmission Service (DTS). In this topic, a MySQL database is used.

Prerequisites

  • A Server Load Balancer (SLB) instance is configured. For more information, see Configure a CLB Instance.
  • An ApsaraDB RDS instance that runs RDS High-availability Edition is created and uses the multi-zone deployment method. For more information about how to create an ApsaraDB RDS instance, see Create an ApsaraDB RDS for MySQL instance.
  • An account is created for the RDS instance. For more information, see Create databases and accounts for an ApsaraDB RDS for MySQL instance.
  • A non-root account is created for the self-managed database hosted on the ECS instance. The account is used for data migration by using Data Transmission Service (DTS).
    For example, you can run the following command to create an account with its username as dts and password as 123456 for a MySQL database:
    grant all on *.*  to 'dts'@'%'  IDENTIFIED BY '123456';

Background information

DTS supports data migration between homogeneous and heterogeneous data sources. It also supports Extract, Transform, Load (ETL) features such as data mapping at three levels (databases, tables, and columns) and data filtering. You can use DTS for zero-downtime migration to minimize the impact on your business. During data migration, the source database continues to provide services normally. For more information about the database types supported by DTS, see Data migration.

Procedure

  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.
  2. From the drop-down list next to Data Migration Tasks, select the region in which your data migration instance resides.
    Note If you use the new DTS console, 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 databases.
    Warning After you select the source and destination instances, we recommend that you read the limits displayed at the top of the page. This helps ensure that the task properly runs or prevent data inconsistency.
    SectionParameterDescription
    NoneTask 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 DatabaseSelect 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 use an existing instance, DTS automatically applies the parameter settings of the source database.
    • If you do not use an existing instance, you must configure the parameters for the database.
    Database TypeThe type of the source database. Select MySQL.
    Access MethodThe access method of the source database. Select an access method based on the deployment location of the source database. In this example, Public IP Address is selected.
    Note If you select other access methods, you must set up the environment that is required for the self-managed database. For more information, see Preparation overview.
    Instance RegionThe region in which the source MySQL database resides.
    Hostname or IP addressThe endpoint that is used to access the source MySQL database. In this example, the public IP address is entered.
    Port NumberThe service port number of the source MySQL database. The port must be accessible over the Internet. Default value: 3306.
    Database AccountThe account of the source MySQL database. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password

    The password of the database account.

    Destination DatabaseSelect 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 use an existing instance, DTS automatically applies the parameter settings of the instance.
    • If you do not use an existing instance, you must configure the parameters for the database.
    Database TypeThe type of the destination database. Select MySQL.
    Access MethodThe access method of the destination instance. In this example, select Alibaba Cloud Instance.
    Instance RegionThe region in which the destination ApsaraDB RDS for MySQL instance resides.
    RDS Instance IDThe ID of the destination ApsaraDB RDS for MySQL instance.
    Database AccountThe database account of the destination instance. For information about the permissions that are required for the account, see Permissions required for database accounts.
    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 a whitelist is configured for your self-managed database, you must add the CIDR blocks of DTS servers to the whitelist. Then, click Test Connectivity and Proceed.
    Warning If the CIDR blocks of DTS servers are automatically or manually added to the whitelist of a database or an 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: 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.
  6. Configure objects to migrate and advanced settings.
    ParameterDescription
    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 Incremental Data Migration is not selected, we recommend that you do not write data to the source instance during data migration. This ensures data consistency between the source and destination instances.
    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 identical table 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 some columns are migrated or the data migration task fails. Proceed with caution.
    Capitalization of Object Names in Destination Instance

    The capitalization of database names, table names, and column 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 Rightwards arrow icon and add the objects to the Selected Objects section.

    Note You can select columns, tables, or schemas as the objects to be migrated. If you select tables or columns as the objects to be migrated, DTS does not migrate other objects, such as views, triggers, or stored procedures, to the destination database.
    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 Use SQL conditions to filter data.
    • To select the SQL operations performed on a specific database or table, right-click an 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 operations that can be migrated, see SQL operations that can be performed for incremental data migration.
  7. Click Next: Advanced Settings to configure advanced settings.
    ParameterDescription
    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:
    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 the gh-ost tool to perform online DDL operations on the source database, you can specify whether to migrate the temporary tables generated by online DDL operations. Valid values:
    Important You cannot use tools such as pt-online-schema-change to perform online DDL operations on the source database. Otherwise, the DTS task fails.
    • Yes: DTS migrates the data of temporary tables generated by online DDL operations.
      Note If online DDL operations generate a large amount of data, the data migration task may take an extended period of time to complete.
    • No, Adapt to DMS Online DDL: DTS does not migrate the data of temporary tables generated by online DDL operations. Only the original DDL operations that are performed by using DMS are migrated.
      Note If you select this option, the tables in the destination database may be locked.
    • No, Adapt to gh-ost: DTS does not migrate the data of temporary tables generated by online DDL operations. Only the original DDL operations that are performed by using the gh-ost tool are migrated. You can use the default or custom regular expressions to filter out the shadow tables of the gh-ost tool and tables that are not required.
      Note If you select this option, the tables in the destination database may be locked.
    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.
    Configure ETL
    Specifies whether to configure the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values:
    Whether to delete SQL operations on heartbeat tables of forward and reverse tasks
    Specifies whether to write SQL operations on heartbeat tables to the source database while the DTS instance is running.
    • Yes: does not write SQL operations on heartbeat tables. In this case, latency of the DTS instance may be displayed.
    • No: writes SQL operations on heartbeat tables. In this case, features such as physical backup and cloning of the source database may be affected.
  8. In the lower part of the page, click Next: Save Task Settings and 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, 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.
    SectionParameterDescription
    ParametersInstance Class

    DTS provides several 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.

What to do next

Configure the endpoint, account, and password of the RDS instance in applications to connect to the RDS instance. You can use Data Management (DMS) or the MySQL client to manage the RDS instance. For more information, see Use a database client or the CLI to connect to an ApsaraDB RDS for MySQL instance.