Use DTS to migrate Amazon RDS for MySQL to Alibaba Cloud - Data Transmission Service

Use Data Transmission Service (DTS) to migrate data from an Amazon RDS for MySQL instance to an ApsaraDB RDS for MySQL instance. DTS supports schema migration, full data migration, and incremental data migration. You can combine these migration types to migrate your database without interrupting your applications.

Prerequisites

Ensure that the publicly accessible option for the Amazon RDS for MySQL instance is set to Yes.
Create an ApsaraDB RDS for MySQL instance with a storage capacity larger than the storage used by the source Amazon RDS for MySQL instance. For more information, see Create an ApsaraDB RDS for MySQL instance.

Limits

During a full data migration, DTS consumes read and write resources on the source and destination databases, increasing their load. If your databases have poor performance, low specifications, or high workloads (for example, if the source database has many slow SQL queries or tables without primary keys, or if deadlocks occur in the destination database), the increased load can strain your databases or even cause service interruptions. Perform the data migration during off-peak hours, such as when the CPU utilization of both databases is below 30%.
If a source table lacks a primary key or a unique constraint and contains non-unique data, duplicate data may be created in the destination database.
For columns with the FLOAT or DOUBLE data type, DTS reads their values by using the ROUND(COLUMN,PRECISION) function. If the precision is not explicitly defined, DTS migrates FLOAT values with a precision of 38 digits and DOUBLE values with a precision of 308 digits. Verify that these precisions meet your business requirements.
If a source database name violates ApsaraDB RDS naming conventions, you must create a compliant database in the destination instance before configuring the task. Otherwise, DTS creates the database automatically.

Note
For more information about naming conventions and how to create a database, see Create a database and accounts.
If a data migration task fails, DTS automatically attempts to resume it. Before you switch your business workloads to the destination instance, make sure to stop or release the task. This prevents an automatically resumed task from overwriting data in the destination instance with data from the source database.

Billing

Migration type	Task configuration fee	Internet traffic fee
Schema migration and full data migration	Free of charge.	DTS charges an Internet traffic fee when the Access Method of the destination database is set to Public IP Address. Billing overview.
Incremental data migration	Charged. Billing overview.

Migration types

Schema migration

DTS migrates object schemas to the destination instance. DTS supports schema migration for tables, views, triggers, stored procedures, and stored functions. 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 stored functions.
- DTS does not migrate user information. To call a view, stored procedure, or stored function in the destination instance, you must grant read and write permissions to the invoker.
Full data migration
DTS migrates all existing data in the selected objects from the Amazon RDS for MySQL instance to the ApsaraDB RDS for MySQL instance.
Note
- During a full data migration, concurrent INSERT operations cause table fragmentation in the destination instance. After the full data migration is complete, the tablespace of the destination instance is larger than that of the source instance.
- Do not perform DDL operations, such as adding a column, on the source instance before the schema migration and full data migration are complete. Otherwise, the data migration may fail.
Incremental data migration

After the full data migration, DTS reads the binlog of the Amazon RDS for MySQL instance to synchronize incremental data updates to the ApsaraDB RDS for MySQL instance. Incremental data migration lets you smoothly migrate your MySQL database without interrupting your applications.

Database account permissions

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

To create database accounts and grant the required permissions, see the following topics:

For an Amazon RDS for MySQL database, see Create an account for a self-managed MySQL database and configure binary logging.
For an ApsaraDB RDS for MySQL database, see Create an account and Modify account permissions.

Before you begin

Log on to the Amazon RDS Management Console.
In the left-side navigation pane, click Database.
Click the DB identifier of the target instance.
In the Security group rules section, click the security group name of the inbound rule.
On the Security Groups page, click the target Security Group ID.
On the Inbound rules tab, click Edit inbound rules.
On the Edit inbound rules page, click Add rule, add the CIDR blocks for the DTS servers in the destination database's region, and then click Save rules. For more information about the DTS CIDR blocks, see Add DTS Server IP Addresses to a Whitelist.
Note
- Add only the CIDR blocks for DTS servers in the destination database's region. For example, if your source database is in the Singapore region and your destination database is in the China (Hangzhou) region, you only need to add the CIDR blocks for DTS servers in the China (Hangzhou) region.
- You can add multiple CIDR blocks to a single rule.
- For more information, see the official AWS documentation or contact AWS Support.
Log on to the Amazon RDS for MySQL database and set the retention period for binary logs. You can skip this step if incremental data migration is not required.
```
call mysql.rds_set_configuration('binlog retention hours', 24);
```
Note
- This command sets the retention period for binary logs to 24 hours. The maximum retention period is 168 hours (7 days).
- Binary logging must be enabled for the Amazon RDS for MySQL instance, and the binlog_format parameter must be set to row. For MySQL 5.6 and later, the binlog_row_image parameter must be set to full. For instructions, see the official AWS documentation or contact AWS Support.

Procedure (new console)

Navigate to the migration task list page for the destination region using one of the following methods.
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.
Click Create Task to navigate to the task configuration page.

Configure the source and destination databases.

Warning

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

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 a DMS database instance.	You can choose whether to use an existing instance, as needed. If you use an existing instance, the database information below is automatically filled in. You do not need to enter it again. If you do not use an existing instance, you must configure the database information below. Note In the DMS console, you can click Add DMS Database Instance to register a database with DMS. For more information, see ApsaraDB Data Ingestion and Register a database hosted on a third-party cloud service or a self-managed database. In the DTS console, you can register a database with DTS on the Database Connections page or the new configuration page. For more information, see Manage database connections.
	Database Type	Select MySQL.
	Connection Type	Select Public IP Address.
	Instance Region	Select the region of the Amazon RDS for MySQL database. Note If the region where your Amazon RDS for MySQL database is located is not available in the drop-down list, select the nearest region.
	Domain Name or IP	Enter the endpoint of the Amazon RDS for MySQL database. Note You can obtain the database endpoint and Port Number on the Connectivity & security tab of the Amazon RDS for MySQL instance.
	Port Number	Enter the service port of the Amazon RDS for MySQL database. The default value is 3306.
	Database Account	Enter the account for the Amazon RDS for MySQL database. For information about the required permissions, see Database account permissions.
	Database Password	Enter the password for the database account.
	Encryption	Select Non-encrypted or SSL-encrypted based on your requirements. If SSL encryption is not enabled for your Amazon RDS for MySQL instance, select Non-encrypted. If SSL encryption is enabled for your Amazon RDS for MySQL instance, select SSL-encrypted. You must also upload a CA Certificate and enter the CA Certificate Password.
Destination Database	Select a DMS database instance.	You can choose whether to use an existing instance, as needed. If you use an existing instance, the database information below is automatically filled in. You do not need to enter it again. If you do not use an existing instance, you must configure the database information below. Note In the DMS console, you can click Add DMS Database Instance to register a database with DMS. For more information, see ApsaraDB Data Ingestion and Register a database hosted on a third-party cloud service or a self-managed database. In the DTS console, you can register a database with DTS on the Database Connections page or the new configuration page. For more information, see Manage database connections.
	Database Type	Select MySQL.
	Connection Type	Select Alibaba Cloud Instance.
	Instance Region	Select the region of the destination RDS for MySQL instance.
	Replicate Data Across Alibaba Cloud Accounts	This scenario involves a migration within the same Alibaba Cloud account. Select No.
	RDS Instance ID	Select the ID of the destination RDS for MySQL instance.
	Database Account	Enter the account for the destination RDS for MySQL instance. For information about the required permissions, see Database account permissions.
	Database Password	Enter the password for the database account.
	Connection Method	Select Non-encrypted or SSL-encrypted based on your database requirements. If you set this parameter to SSL-encrypted, you must enable SSL encryption for the RDS for MySQL instance beforehand. For more information, see Quickly enable SSL encryption using a cloud certificate.

After you complete the configuration, click Test Connectivity and Proceed at the bottom of the page. In the CIDR Blocks of DTS Servers dialog box that appears, click Test Connectivity.

Note
Ensure that the IP address segments of the DTS service are 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.

Configure the task objects.

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 include triggers, you can skip this parameter. For more information, see Configure how to synchronize or migrate triggers. Note This parameter is available only if you select Migration Types for Schema Migration.
Enable Migration Assessment	This feature assesses whether the schemas of the source and destination databases (such as index length, stored procedures, and dependent tables) meet the requirements. Select Yes or No. Note This parameter is available only if you select Migration Types for Schema Migration. If you select Yes, the precheck may take longer. You can view the Assessment Result during the precheck phase. The assessment result does 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.
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	Select one or more objects from the Source Objects section. Click the icon and add the objects to the Selected Objects section. Note The granularity for selecting migration objects is schema, 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 change the name of a single migration object in the target instance, right-click the object in the Selected Objects box. For more information, see Map individual schema, table, and column names. To change the names of multiple migration objects in the target instance, click Selected Objects in the upper-right corner of the Batch Edit box. For more information, see Map multiple schema, table, and column names. Note If you use the object name mapping feature, the migration of other objects that depend on the mapped object may fail. To filter data by using a WHERE clause, right-click the table in the Selected Objects box, and set the filter condition in the dialog box that appears. For instructions, see Configure filter conditions. To select SQL operations to migrate at the database or table level, right-click the object in the Selected Objects box and select the desired SQL operations in the dialog box that appears.

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	Select whether to migrate account information from the source database. If you select Yes, you must also select the accounts to be migrated and confirm their permissions. For more information about authorization methods, see Migrate database accounts.
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.
Environment Tag	You can select an environment tag to identify the instance. This is not required for this example.
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.
Configure ETL	Based on your business needs, select whether to configure the ETL feature to process data. Yes: Configures the ETL feature. You must also enter data processing statements in the text box. No: Does not configure 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.

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

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

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.

Purchase the instance.

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

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?
New Instance Class	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.

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

Procedure (old console)

Log on to the DTS console.

Note
If you are automatically redirected to the Data Management (DMS) console, you can click the icon in the lower-right corner and then click to return to the classic DTS console.
In the left-side navigation pane, click Data Migration.
At the top of the Migration Tasks page, select the region of the destination cluster.
In the upper-right corner of the page, click Create Data Migration Task.