Data Transmission Service (DTS) supports migrating data from RDS instances of other Alibaba Cloud accounts to RDS instances of the current Alibaba Cloud account. This topic describes how to log on to the console using the Alibaba Cloud account (primary account) to which the destination RDS instance belongs and migrate data from RDS instances of other Alibaba Cloud accounts.
Prerequisites
You can retrieve the IDs of the Alibaba Cloud account (primary account) associated with both the source and destination RDS instances. For more information, see Preparations.
You can carry out authorization tasks with the Alibaba Cloud account that owns the RDS instance, including creating a RAM role, assigning specific permissions, and updating the trust policy. For more information, see Preparations.
The storage space of the created destination RDS instance must be larger than the used storage space of the source RDS instance.
NoteFor information on the versions supported by the source and destination database instances, see Migration Overview.
Considerations
For more information, see non-cross-account documents such as:
For information on migrating between RDS MySQL instances, see Migration Between RDS MySQL Instances.
Billing rules
Migration type | Task configuration fee | Internet traffic fee |
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 Billing overview. |
Incremental data migration | Charged. For more information, see Billing overview. |
Permissions required for migration accounts
Migration between RDS MySQL instances
Database type | Schema migration | Full data migration | Incremental data migration |
The source ApsaraDB RDS for MySQL instance | The SELECT permission | The SELECT permission | Read and write permissions |
Destination ApsaraDB RDS for MySQL instance | Read and write permissions | Read and write permissions | Read and write permissions |
For instructions on creating and granting permissions to database accounts for RDS MySQL instances, see Create an account and Modify account permissions.
If the source database account that you use is not created and granted permissions in the ApsaraDB RDS for MySQL console, make sure that the account has the REPLICATION CLIENT, REPLICATION SLAVE, SHOW VIEW, and SELECT permissions.
If you want to migrate the account information of the source database, additional permissions are required for the source and destination database accounts that are used when you configure the DTS task. For more information, see Migrate database accounts.
Migration between RDS MariaDB instances
Database | Schema migration | Full data migration | Incremental data migration |
Source ApsaraDB RDS for MariaDB instance | The SELECT permission | The SELECT permission | The read and write permissions |
Destination ApsaraDB RDS for MariaDB instance | The read and write permissions | The read and write permissions | The read and write permissions |
For information about how to create a database account and grant permissions to the database account in an ApsaraDB RDS for MariaDB instance, see Create an account and Modify or reset account permissions.
Migration between RDS PostgreSQL instances
Database type | Schema migration | Full data migration | Incremental data migration |
Source ApsaraDB RDS for PostgreSQL instance | The USAGE permission on the pg_catalog schema | The SELECT permission on the objects to be migrated | Permissions of a privileged account that is the owner of the database Note If the source ApsaraDB RDS for PostgreSQL instance runs PostgreSQL 9.4 and you want to migrate only DML operations, only the REPLICATION permission is required for the database account. |
Destination ApsaraDB RDS for PostgreSQL instance | The CREATE and USAGE permissions on the objects to be migrated | The permissions of the schema owner |
RDS PostgreSQL instance database account creation and authorization methods can be found in create account and create database documentation.
Migration between RDS SQL Server instances
Database | Schema migration | Full migration | Incremental migration |
Source RDS SQL Server instance | SELECT permission | SELECT permission | Permissions of the object owner |
Destination RDS SQL Server instance | Access control list | Access control list | Access control list |
For methods on creating database accounts and authorizing them in an RDS SQL Server instance, see how to create standard and privileged accounts and how to modify account permissions.
Procedure
Preparations
Configure RAM authorization for the Alibaba Cloud account associated with the database instance. For more information, see How to configure RAM authorization for cross-account tasks.
Configure a cross-account migration instance
This example uses a cross-account source RDS MySQL instance to describe how to configure a cross-account migration instance.
Access the migration task list page using the Alibaba Cloud account (primary account) associated with the destination RDS instance.
DTS console
Log on to the DTS console.
In the left-side navigation pane, click Data Migration.
In the upper-left corner of the page, select the region in which the data migration instance resides.
DMS console
NoteThe actual operation 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.
Log on to the DMS console.
In the top navigation bar, move the pointer over
.From the drop-down list to the right of Data Migration Tasks, select the region in which the data synchronization instance resides.
Click Create Task to go to the task configuration page.
Configure the source and destination databases. The following table describes the parameters.
Category
Configuration
Description
None
Task Name
The name of the DTS task. DTS automatically generates a task name. We recommend that you specify an informative name that makes it easy to identify the task. You do not need to specify a unique task name.
Source Database
Select Existing Connection
The 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 use an existing instance, you must configure the database information below.
NoteYou can register a database with DTS on the Database Connections page or the new configuration page. For more information, see Manage database connections.
In the DMS console, you can select an existing database from the Select a DMS database instance. drop-down list. You can also click Add DMS Database Instance or go back to the homepage of the DMS console to register a database with DMS. For more information, see Register an Alibaba Cloud database instance and Register a database hosted on a third-party cloud service or a self-managed database.
Database Type
Select MySQL.
Access Method
Select Cloud Instance.
Instance Region
Select the region where the source RDS instance resides.
NoteYou can select different regions for the source and destination RDS instances.
Cross Alibaba Cloud Account
Select Cross-account.
Cross Alibaba Cloud Account
Enter the ID of the Alibaba Cloud account (primary account) to which the source RDS instance belongs.
NoteFor more information, see Obtain the ID of the Alibaba Cloud account (primary account) to which the source database belongs.
Cross Alibaba Cloud Account Role Name
Enter the name of the RAM role created by using the Alibaba Cloud account (primary account) to which the source RDS instance belongs (for example, ram-for-dts).
NoteDo not enter the default role of DTS AliyunDTSDefaultRole.
Do not enter the ARN of the RAM role.
For more information about how to create a RAM role, see Step 1: Create a RAM role.
RDS Instance ID
Select the instance ID of the source RDS instance.
NoteIf an alert message appears when you select an RDS instance ID, modify the parameter values as prompted. For more information about common alert messages, see Common errors.
Database Account
Enter the account of the source MySQL database. For more information about the required permissions, see Database account permissions.
Database Password
The password that is used to access the database instance.
Connection Method
Select Non-encrypted Connection or Ssl-encrypted Connection based on your needs. In this example, Non-encrypted Connection is selected.
NoteIf you select Ssl-encrypted Connection, you must enable the SSL encryption feature for the RDS instance in advance. For more information, see Enable SSL encryption.
Destination Database
Select Existing Connection
The 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 use an existing instance, you must configure the database information below.
NoteYou can register a database with DTS on the Database Connections page or the new configuration page. For more information, see Manage database connections.
In the DMS console, you can select an existing database from the Select a DMS database instance. drop-down list. You can also click Add DMS Database Instance or go back to the homepage of the DMS console to register a database with DMS. For more information, see Register an Alibaba Cloud database instance and Register a database hosted on a third-party cloud service or a self-managed database.
Database Type
Select MySQL.
Access Method
Select Cloud Instance.
Instance Region
Select the region where the destination RDS instance resides.
NoteYou can select different regions for the source and destination RDS instances.
Replicate Data Across Alibaba Cloud Accounts
In this example, No is selected.
RDS Instance ID
Select the instance ID of the destination RDS instance.
Database Account
Enter the account of the destination MySQL database. For more information about the required permissions, see Database account permissions.
Database Password
The password that is used to access the database instance.
Connection Method
Select Non-encrypted Connection or Ssl-encrypted Connection based on your needs. In this example, Non-encrypted Connection is selected.
NoteIf you select Ssl-encrypted Connection, you must enable the SSL encryption feature for the RDS instance in advance. For more information, see Enable SSL encryption.
In the lower part of the page, click Test Connectivity and Proceed.
NoteMake sure that the CIDR blocks of DTS servers can be 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 the CIDR blocks of DTS servers.
If the source or destination database is a self-managed database and its Access Method is not set to Alibaba Cloud Instance, click Test Connectivity in the CIDR Blocks of DTS Servers dialog box.
Configure the objects to be migrated.
On the Configure Objects page, configure the objects that you want to migrate.
Configuration
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.
NoteIf you do not select Schema Migration, make sure a database and a table are created in the destination database to receive data and the object name mapping feature is enabled in Selected Objects.
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.
Method to Migrate Triggers in Source Database
Choose a migration method for triggers that suits your requirements. If the objects you're migrating don't include triggers, configuring this parameter is unnecessary. For more information, see how to configure trigger synchronization or migration.
NoteYou can only configure this parameter if you select Migration Types, Schema Migration, and Incremental Data Migration.
Enable Migration Assessment
Assess whether the structure of the source and destination databases, such as index length, stored procedures, and dependent tables, meets the requirements. You can select Yes or No, based on your actual needs.
NoteThis parameter can only be configured if you select Migration Types and Schema Migration.
If you select Yes, the precheck time may increase. You can view the Assessment Result during the precheck phase. The assessment results do not affect the precheck results.
Processing Mode of Conflicting Tables
Precheck and Report Errors: checks whether the destination database contains tables that use the same names as tables in the source database. If the source and destination databases do not contain tables that have identical table names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started.
NoteIf the source and destination databases contain tables with identical names and the tables in the destination database cannot be deleted or renamed, you can use the object name mapping feature to rename the tables that are migrated to the destination database. For more information, see Map object names.
Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases.
WarningIf you select Ignore Errors and Proceed, data inconsistency may occur and your business may be exposed to the following potential risks:
If the source and destination databases have the same schema, and a data record has the same primary key as an existing data record in the destination database, the following scenarios may occur:
During full data migration, DTS does not migrate the data record to the destination database. The existing data record in the destination database is retained.
During incremental data migration, DTS migrates the data record to the destination database. The existing data record in the destination database is overwritten.
If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
Whether to migrate Event
Select whether to migrate events from the source database according to your needs. If you choose Yes, you must also adhere to the relevant requirements and carry out the necessary operations. For more information, see Synchronize or migrate events.
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 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 Source Objects section. Click the
icon to add the objects to the Selected Objects section.
NoteYou can select columns, tables, or databases 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 specify the name of an object to be migrated in the destination instance or specify the object to receive data in the destination instance, right-click the object in the Selected Objects section. For more information, see Map object names.
To remove one or more objects that are selected for migration, click the objects in the Selected Objects section and then click the
icon to move the objects to the Source Objects section.
NoteIf 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 Specify filter conditions.
To select the SQL operations for incremental migration, right-click an object in the Selected Objects section. In the dialog box that appears, select the SQL operations that you want to migrate.
Click Next: Advanced Settings to configure advanced settings.
Configuration
Description
Dedicated Cluster for Task Scheduling
By default, DTS schedules the data migration task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data migration tasks, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.
Copy the temporary table of the Online DDL tool that is generated in the source table to the destination database.
If you use DMS or the gh-ost tool to perform online DDL operations on the source database, you can specify whether to migrate the data of temporary tables generated by online DDL operations. Valid values:
ImportantYou 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.
NoteIf online DDL operations generate a large amount of data, latency may occur for the data migration task.
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.
NoteIf 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.
NoteIf you select this option, the tables in the destination database may be locked.
Whether to Migrate Accounts
Choose to migrate the account information from the source database according to your requirements. If you opt for Yes, you must also select which accounts to migrate and verify their permissions.
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 1,440. 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.
NoteIf 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.
Retry Time for Other Issues
The retry time range for other issues. For example, if DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry 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 retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails.
ImportantThe value of the Retry Time for Other Issues parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
Enable Throttling for Full Data Migration
Specifies whether to 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 of the database servers. You can enable throttling for full data migration based on your business requirements. To configure throttling, you must configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) parameters. This reduces the loads of the destination database server.
NoteYou can configure this parameter only if you select Full Data Migration for the Migration Types parameter.
Enable Throttling for Incremental Data Migration
Specifies whether to enable throttling for incremental data migration. To configure throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This reduces the loads of the destination database server.
NoteYou can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.
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. Valid values:
Yes: does not write SQL operations on heartbeat tables. In this case, a 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.
Environment Tag
You can select an environment tag to identify the instance based on your actual needs. In this example, you do not need to configure this parameter.
Configure ETL
Specifies whether to enable 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.
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.
Click Next Step: Data Verification to configure the data verification task.
For more information about how to use the data verification feature, see Configure a data verification task.
Save the task settings and run a precheck.
To view the parameters to be specified when you call the relevant API operation to configure the DTS task, move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters.
If you do not need to view or have viewed the parameters, click Next: Save Task Settings and Precheck in the lower part of the page.
NoteBefore 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.
Purchase an instance.
Wait until Success Rate becomes 100%. Then, click Next: Purchase Instance.
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.
Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.
Click Buy and Start. In the message that appears, click OK.
You can view the progress of the task on the Data Migration page.