This topic describes how to migrate data from an Amazon RDS for MySQL instance to an ApsaraDB RDS for MySQL instance by using Data Transmission Service (DTS). DTS supports schema migration, full data migration, and incremental data migration. You can select all of the supported migration types to ensure service continuity.

Prerequisites

  • The Public accessibility option of the Amazon RDS for MySQL instance is set to Yes. This ensures that DTS can access the Amazon RDS for MySQL instance over the Internet.
  • An ApsaraDB RDS for MySQL instance is created. For more information, see Create an ApsaraDB RDS for MySQL instance.
  • The available storage space of the ApsaraDB RDS for MySQL instance is larger than the total size of the data in the Amazon RDS for MySQL instance.

Precautions

  • DTS uses read and write resources of the source and destination databases during full data migration. This may increase the database load. 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 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 usage of the source and destination databases is less than 30%.
  • The source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, duplicate data may exist in the destination database.
  • DTS uses the ROUND(COLUMN,PRECISION) function to retrieve values from columns of the float or double data type. If the precision is not specified, 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 how to create a database and the database naming conventions, see Create databases and accounts.
  • DTS automatically resumes a failed data migration task. Before you switch your workloads to the destination database, stop or release the data migration task. Otherwise, the data in the source database will overwrite the data in the destination database after the task is resumed.

Billing

Migration type Instance configurations Internet traffic
Schema migration and full data migration Free of charge. Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Pricing.
Incremental data migration Charged. For more information, see Pricing.

Migration types

  • Schema migration

    DTS migrates the schemas of the required objects to the destination instance. DTS supports schema migration for the following types of objects: table, view, trigger, stored procedure, and function. DTS does not support schema migration for events.

    Note
    • During schema migration, DTS changes the value of the SECURITY attribute from DEFINER to INVOKER for views, stored procedures, and functions.
    • DTS does not migrate user information. Before a user can call views, stored procedures, and functions of the destination database, you must grant the read/write permissions to the user.
  • Full data migration
    DTS migrates historical data of the required objects from the Amazon RDS for MySQL instance to the ApsaraDB RDS for MySQL instance.
    Note
    • During full data migration, concurrent INSERT operations cause fragmentation in the tables of the destination instance. After full data migration is complete, the tablespace of the destination instance is larger than that of the source instance.
    • During schema migration and full data migration, do not perform DDL operations in the source database, for example, add a field. Otherwise, data migration may fail.
  • Incremental data migration

    After full data migration is complete, DTS retrieves binary log files from the Amazon RDS for MySQL instance. Then, DTS synchronizes incremental data from the Amazon RDS for MySQL instance to the ApsaraDB RDS for MySQL instance. Incremental data migration allows you to ensure service continuity when you migrate data between MySQL databases.

Permissions required for database accounts

Database Schema migration Full data migration Incremental data migration
Amazon RDS for MySQL The SELECT permission The SELECT permission The REPLICATION CLIENT, REPLICATION SLAVE, SHOW VIEW, and SELECT permissions
ApsaraDB RDS for MySQL The read/write permissions The read/write permissions The read/write permissions

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

Before you begin

  1. Log on to the Amazon RDS Management Console.
  2. Go to the Basic information page of the Amazon RDS for MySQL instance.
  3. In the Security group rules section, click the name of the security group corresponding to the existing inbound rule.
    Security group rules
  4. On the Security groups page, click the Inbound tab in the Security group section. On the Inbound tab, click Edit to add the CIDR blocks of DTS servers 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.
    Edit inbound rules
    Note
    • You need to add only the CIDR blocks of DTS servers that are located in the same region as the destination database. For example, the source database is located in Singapore and the destination database is located in Hangzhou. You need to add only the CIDR blocks of DTS servers that are located in the China (Hangzhou) region.
    • You can add all of the required CIDR blocks to the inbound rule at a time.
  5. Log on to the Amazon RDS for MySQL database and specify the number of hours to retain binary log files. Skip this step if you do not need to perform incremental data migration.
    call mysql.rds_set_configuration('binlog retention hours', 24);
    Note
    • The preceding command sets the retention period of binary log files to 24 hours. The maximum value is 168 hours (7 days).
    • The binary logging feature of the Amazon RDS for MySQL instance must be enabled and the value of the binlog_format parameter must be set to row. If the version of MySQL is 5.6 or later, the value of the binlog_row_image parameter must be set to full.

Procedure

  1. Log on to 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.
    Select a region
  4. In the upper-right corner of the page, click Create Migration Task.
  5. Configure the source and destination databases for the data migration task.
    Configure the source and destination databases
    Section Parameter Description
    N/A Task Name DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
    Source Database Instance Type Select User-Created Database with Public IP Address.
    Instance Region If the instance type is set to User-Created Database with Public IP Address, you do not need to specify the instance region.
    Database Type Select MySQL.
    Hostname or IP Address Enter the endpoint that is used to connect to the Amazon RDS for MySQL instance.
    Note You can obtain the endpoint on the Basic information page of the Amazon RDS for MySQL instance.
    Endpoint
    Port Number Enter the service port number of the Amazon RDS for MySQL instance. The default port number is 3306.
    Database Account Enter the database account of the Amazon RDS for MySQL instance. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password Enter the password of the source 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 appears. If the Failed message appears, click Check next to Failed. Modify the source database parameters based on the check results.
    Destination Database Instance Type Select RDS Instance.
    Instance Region Select the region where the ApsaraDB RDS for MySQL instance resides.
    RDS Instance ID Select the ID of the ApsaraDB RDS for MySQL instance.
    Database Account Enter the database account of the ApsaraDB RDS for MySQL instance. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password Enter the password of the destination 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 appears. If the Failed message appears, click Check next to Failed. Modify the destination database parameters based on the check results.
    Encryption Select Non-encrypted or SSL-encrypted. If you want to select SSL-encrypted, you must enable SSL encryption for the RDS instance before you configure the data migration task. For more information, see Configure SSL encryption for an RDS MySQL instance.
    Note The Encryption parameter is available only for regions in mainland China and the China (Hong Kong) region.
  6. In the lower-right corner of the page, click Set Whitelist and Next.
    Note DTS adds the CIDR blocks of DTS servers to the whitelist of the ApsaraDB RDS for MySQL instance. This ensures that DTS servers can connect to the ApsaraDB RDS for MySQL instance.
  7. Select the migration types and objects to be migrated.
    Select the migration types and objects to be migrated
    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 Incremental Data Migration is not selected, do not write data to the source database during full data migration. This ensures data consistency between the source and destination databases.
    • During schema migration and full data migration, do not perform DDL operations on the objects to be migrated. Otherwise, the objects may fail to be migrated.
    Objects

    Select objects from the Available section and click the Right arrow icon to move the objects to the Selected section.

    Note
    • You can select columns, tables, or databases as the objects to be migrated.
    • After an object is migrated to the destination database, the name of the object remains unchanged. You can change the names of the objects that are migrated to the destination database by using the object name mapping feature. For more information about how to use this feature, see Object name mapping.
    • If you use the object name mapping feature on an object, other objects that are dependent on the object may fail to be migrated.
  8. In the lower-right corner of the page, click Precheck.
    Notice
    • Before you can start the data migration task, a precheck is performed. A data migration task can be started only if it passes the precheck.
    • If the task fails to pass the precheck, click the Info icon icon next to each failed item to view details. Troubleshoot the issues based on the causes and perform 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 a data migration task. Otherwise, data migrated to the destination database will be incomplete. 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 migration task.

      Notice Select an appropriate time to manually stop the migration task. For example, you can stop the migration task during off-peak hours or before you switch your workloads to the destination instance.
      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 delay time of incremental data migration may be displayed in the progress bar.
      2. After the status of incremental data migration changes to The migration task is not delayed, manually stop the migration task.Stop an incremental data migration task
  12. Switch your workloads to the ApsaraDB RDS for MySQL instance.