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Database Transmission Service

Data migration

Migrating on-premises self-managed databases to the cloud via DTS

In the scenario of business migration, after the local database is migrated to the cloud, you need to cut the traffic to switch the business to the cloud. To avoid exceptions in the database on the cloud after the business traffic is cut, it is recommended to use the DTS data migration function to configure a reverse migration link. When a business exception occurs, you can immediately switch the business to the local self-managed database. This topic uses an on-premises self-managed MySQL database instance and a Volcano Engine RDS for MySQL as examples to introduce how to use DTS to migrate on-premises data to the cloud, switch services, migrate data back, and roll back services.

Prerequisites

The local self-built database and the VPC of Volcano Engine have been connected. Select a configuration method as needed according to the actual situation:

When using VPN to perform data migration, the local network where the self-managed database is located has been connected to Volcano Engine via VPN gateway. For detailed steps, refer to Building a cloud VPC and on-premises multi-data-center network interconnection.

If data migration requires a dedicated line connection, you need to establish a dedicated line connection between a single cloud VPC and a single on-premises data center network. For more information, refer to Configuring direct connections.

An instance and database for RDS for MySQL have been created. Used to migrate local self-built data to the cloud. For details, refer to Creating an instance (RDS for MySQL) and Creating a database.

When the database instance’s access method is VPC and access restrictions are enabled, add the subnet segment of the VPC connected by the dedicated line to the database instance’s allowlist or security group before creating the database transmission task. For more information, refer to Adding the CIDR block of the DTS server.

Ensure that the servers to which the source and target ends belong have sufficient outbound bandwidth. Otherwise, the data migration rate will be affected.

Precautions

Forward migration and reverse migration are two independent unidirectional migration tasks. Each independent task's constraints, operational restrictions, and other requirements must meet the basic requirements of the migration task. For precautions during the data migration process, please refer to Migrating MySQL connected over express network to Volcano Engine RDS for MySQL, and Migrating Volcano Engine RDS for MySQL to MySQL connected over express network.

During the full migration process, the target database will generate a large number of Binlog files, resulting in the target database's disk usage being much greater than that of the original instance. We recommend that you modify the target database Binlog storage strategy before performing a full migration.

Before starting the reverse migration task, the forward migration task must be paused first; otherwise, data loops may occur.

Since performing a business switching operation requires stopping database writes and pausing business operations, it is recommended to perform the operation during off-peak hours to minimize the impact on business operations.

Database account minimum permission policy

Database	Schema migration	Full migration	Incremental migration
Source	SELECT permission	SELECT permission	REPLICATION SLAVE, REPLICATION CLIENT, and SELECT permissions.
Target	SELECT permission	SELECT permission	REPLICATION SLAVE, REPLICATION CLIENT, and SELECT permissions.

Operation process

In the scenario of business relocation, after the local database is migrated to the cloud, business switching is required. To avoid exceptions in the cloud database after the business is switched, it is recommended to use the Database Transmission Service (DTS) data migration feature to configure a reverse migration link. When a business exception occurs, you can immediately switch the business to the local database. The main procedure is as follows:

Create and start a forward migration task

For the forward task, select Schema migration + Full migration + Incremental migration to migrate the local self-built database to the cloud database.

Create a reverse migration task, but do not start it

For the reverse task, select Incremental migration. Create the task but do not start it to avoid data loopbacks.

Switch the business to the cloud database

Pause business writes to the source local self-built database and switch the business to the cloud database.

Pause the forward migration task and start the reverse migration task

Migrate incremental data generated by the destination cloud database to the local self-built database to provide a rollback solution for the business.

(Optional) Business rollback

If an exception occurs in the cloud service, you can switch the service to the local self-built database.

Procedure

Step 1: Create a forward migration task

Log on to the DTS console.

On the top menu bar, select the project and region.

In the left navigation bar, click Data migration.

On the Migration task list page, click Create task.

On the Create migration task page, locate the Configure source and target database wizard, and configure the following parameters.

Type	Name	Description
None	Task name	Optional. Customize the task name. Naming rules are as follows: Must start with a Chinese character or letter. Must be 64 characters or less. It can contain only Chinese characters, letters, digits, underscores (_), and hyphens (-).
None		Link specification	Select the link specification for the migration task. Compact, Medium and Standard are supported. tip The link specification can not be modified after the task is successfully created. For details on the link specifications, refer to Product specifications.
Source database configuration	Select an existing data source	You can choose whether to use an existing instance as needed: Use existing instances: Click Select an existing data source, then in the Select data source control panel, choose the target region from the Region drop-down list, and select the target data source. Supports selecting data sources by data source name and ID. For methods to create data sources, refer to Data source management. Do not use existing instances: If not using an existing instance, you need to configure the following database instance information.
		Instance type	Select MySQL.
		Access method	Select MySQL connected over express network.
		Region	Select the region of the virtual private cloud.
		Host address	Enter the host address of the MySQL instance connected over express network.
		Port	Enter the port of the MySQL instance connected over express network.
		VPC	Select the target VPC from the drop-down list as follows: Direct connect: Select any VPC under the CEN when achieving data connectivity through a dedicated line CEN. VPN connection: Select the VPC bound to the VPN gateway when achieving data connectivity through VPN.
		Subnet	Select a subnet within the VPC from the drop-down list. tip When migrating a MySQL instance connected over express network, you need to add subnet CIDR block access permissions to the allowlist or security group policy on the source end in advance. Click View subnet CIDR blocks to view and copy CIDR blocks.
		Database account	Enter the database account of the target instance.
		Database password	Enter the password corresponding to the database account of the target instance.
		Test connection	Click Test connection to verify the connection to the instance. If the test connection fails, modify the configuration based on the failure prompt, and then click Test connection again to verify the connection. The details are as follows: Connection authentication failed. Check the network: When this error prompt appears, confirm network connectivity. Connection authentication failed. Check the username and password: When this error prompt appears, verify your username and password. Connection authentication failed, unable to create connection normally, contact customer service: When this error prompt appears, submit a ticket to contact technical staff. Invalid IP address: When this error prompt appears, verify the accuracy of the IP address. The Express network requires the subnet to have * available IPs. The current number of available IPs in the subnet is insufficient, and the task can not be created. Check the subnet resources in the VPC: When this error prompt appears, adjust the number of available IPs in the VPC subnet to ensure enough IPs in the target VPC subnet.
Target database configuration	Select an existing data source	You can choose whether to use an existing instance as needed: Use existing instances: Click Select an existing data source, then in the Select data source control panel, choose the target region from the Region drop-down list, and select the target data source. Supports selecting data sources by data source name and ID. For methods to create data sources, refer to Data source management. Do not use existing instances: If not using an existing instance, you need to configure the following database instance information.
		Instance type	Select MySQL.
		Access method	Select Volcano Engine RDS for MySQL.
		Region	Select the region where the target instance is located.
		MySQL instance	Select the target instance of RDS for MySQL from the drop-down list. tip The drop-down list only shows the first 10 instances. You can also search for the target instance by instance ID or name.
		Database account	Enter the database account of the target instance.
		Database password	Enter the password corresponding to the database account of the target instance.
		Test connection	Click Test connection to verify the connection to the instance. If the test connection fails, modify the configuration based on the failure prompt, and then click Test connection again to verify the connection. The details are as follows: Connection authentication failed. Check if the username and password are correct: When this error prompt appears, verify your username and password. Connection authentication failed, unable to create connection normally, contact customer service: When this error prompt appears, submit a ticket for technical support.
None	Project	Optional. Select the affiliated project for the task from the drop-down list. By default, it is under default (default project). You can also click Create new project to create a new project. For more information, refer to Creating a new project. tip To grant sub-user privileges to access resources in a specific project, refer to Modifying project privileges. After a task is created successfully, if you need to change its affiliated project, you can move the resource to another project. For more information, refer to Moving resources to a project. A project is a virtual concept that includes a set of resources, users, and roles. A project allows for a unified view and management of a set of resources, and controls the permissions of users and roles within the project for those resources.
		Tag	(Optional) Click Add tag to add a tag to the instance. Tags can help you categorize cloud resources, control access to them, and allocate bills and costs. A tag is a key-value pair that identifies a cloud resource. You can use tags to categorize resources with the same characteristics from different dimensions, such as purpose or owner, making it easier to filter, aggregate, and manage your cloud resources. For more details about tags, refer to Tag overview. The rules for tag key-value pairs are as follows: Key Supports any language, characters, numbers, spaces, or symbols (_.:/=+-@). Case-sensitive, and the length is 1 to 128 characters. In UTF-8 encoded Unicode format. Keys cannot start with any form of volc:, such as Volc: or VOLC:. (Optional) Value Supports any language, character, digit, space, or symbol (_.:/=+-@). Case-sensitive, and the length is 0 to 256 characters. In UTF-8 encoded Unicode format. tip A maximum of 20 tags can be associated with a task in a single operation. A maximum of 50 tags can be associated with a single task. For a single resource, tag keys must be unique, and each tag key can have only one value.
		Billing method	Currently, only Pay-as-you-go is supported. No selection is required. tip For detailed billing information, refer to Billing instructions.

Click Next step: configure migration object.

On the Configure migration object wizard page, configure the related parameter information as shown in the table below.

Name	Description
Migration type	Check Structural migration, Full migration, and Incremental migration. tip If User migration is needed, user and permission migration must be handled separately. If some source database accounts do not support migration, ensure that business operations are not affected by the absence of these accounts.
Migration user	Select the target accounts as needed, and set a new password in the New password (Optional) column. When migrating multiple users, click Batch change passwords to change all their passwords at once. Otherwise, the target account passwords will be the same as the source passwords. tip This configuration is supported when Migration type is set to User migration.
Migration starting point	Set to pull Binlog logs from a specified position or timestamp. The values are as follows: System default: The default is the task start time. Specify GTID: Enter the specified GTID in the input box, formatted as source_id:transaction_id. Set GTID_EXECUTED: Enter the specified GTID_EXECUTED in the input box, formatted as source_id:transaction_id. If multiple exist, separate them with commas (,). For how to obtain the instance's GTID_EXECUTED, refer to How to obtain the GTID_EXECUTED of the instance. Specify timestamp: Click the input box to select a date, click Select time to set the time point, then click OK. tip You can configure this parameter when selecting Migration type as Incremental migration. When Migration type selects both Full migration and Incremental migration, migration defaults to the current time point. GTID and GTID_EXECUTED must be legal values from the source end. Otherwise, pre-check reports an error. When selecting Specify timestamp, the time you set must be later than the earliest Binlog time on the source end. If there is no corresponding time Binlog, the closest Binlog starting point will be selected.
Whether to enable foreign key check?	Select whether to enable foreign key check as needed. When enabled, the tool supports migrating cascading updates and deletes of foreign keys from the source, ensuring data integrity and consistency throughout the migration.
Migration object	Check the objects to migrate in the Migration object area. You can use Normal search and Global search to find target objects. At the same time, you can perform the following operations in the Selected object area: Rename databases or tables: Click the pencil icon next to the target database, table, or view to rename them. If you select entire databases in the Migration object area, you can only modify the database name in the Selected object area, and can not expand the database. Filter and delete unnecessary targets: The search box in the Selected object area supports fuzzy search to batch delete unwanted databases, tables, and other targets. Filter data in tables: Check Filter data enables filtering of data within the table. tip Regular expression search for target objects is supported in the Migration object or Selected object areas. When the migration object is not the entire database, OnlineDDL operations are not supported. Meanwhile, incremental migration does not automatically migrate newly added objects and their changes. The migration object granularity can be either database or table. If tables are selected as the migration objects, other objects such as views, triggers, functions, or stored procedures will not be migrated to the target database. To ensure data migration performance and task stability, the source TRIGGER and EVENT will migrate only after the incremental migration completes.
Filter condition	Optional. Filtering data during a full data scan improves migration performance. Click the pen icon in the Filter condition column for the target database, table, or view, set the filter condition, then click Verification statement to validate the condition. tip This feature is currently in beta testing. To use it, submit a ticket for technical support. This field can be configured only if Filter data is selected for the Migration object's database, table, or view. Filter condition currently supported =, !=, <, >, <=, >=, in, is null, and , or.
Error retry time	If a migration task fails due to a disconnection between the source and target ends, the system immediately retries connecting to them multiple times within the specified time. Value range: 600 - 86,400, in seconds (s). The default value is 600 seconds.
Full migration rate	Set the full migration rate as needed. To prevent high migration rates from affecting the source database's performance, adjust the following parameters based on the read and write pressure of the source and target databases accordingly: Rows migrated per second: Enable and set the rows migrated per second as needed. The default value is 100,000, and the value range is 1 to 100,000. Data volume migrated per second: Enable and set the data volume migrated per second as needed. The default value is 25,000. The value range is 1 to 25,000, and the unit is KB. Migration task concurrency: Set the concurrency of migration tasks as needed. The default value is 8, the value range is 1-64. tip You can configure this parameter when selecting Migration type as Full migration. If you apply to enable the full-incremental feature of the DTS, you can not set the migration task concurrency individually. To enable the full-incremental feature of DTS, submit a ticket for technical support.

Click Data validation configuration.

On the Create migration task page, locate the Configure data verification wizard, and configure the following parameters.

Name	Description
Data verification	Select whether to configure the data verification function directly when creating a migration task (built-in). Enable: Configure data verification tasks directly when creating a data migration task. Disable: Do not configure data verification tasks when creating a data migration task.
Validation type	DTS automatically generates validation types based on the database type and migration type, and does not support modification. For more information on validation types, refer to Background.
Validation object	Select the object to be verified as needed. Consistent with the migration task: The object to be verified matches the object to be migrated, meaning all migration objects are verified. Custom: Select the object to be verified as needed.
Startup settings	Configure the timing of data verification in the migration task. Automatic start: The data verification task starts automatically along with the progress of the migration task. Automatic start occurs when full migration (if any) is complete and the delay of incremental migration is 0. Manually start: The data verification task does not start automatically with the migration task progress. You must manually start the data verification at the appropriate time. It is recommended to manually start data verification only after full migration (if any) is complete and the delay of incremental migration is 0. Otherwise, verification results may be inaccurate.
Billing type	Currently, only Pay-as-you-go is supported and can not be modified.

Click Pre-check.

Optional. If a pre-check has been performed for the created task, you can confirm whether to restart the pre-check based on the prompts. If you need to restart, click OK in the Whether to restart the pre-check dialog box.

If the instances of the source and target databases are not modified, there is no need to restart the pre-check.

If you modify the source and target database instance information or the migration task parameters, it is recommended to restart the pre-check to avoid task startup failures or interruptions.

On the Pre-check configuration wizard page, perform the following actions based on the check result:

Click Details in the Actions column of the pre-check results to view detailed alert and failure messages. After modifying the databases and tables accordingly, click Retry.

Click Ignore in the Actions column to ignore the alert and continue starting the migration task. You can also click Ignore all to ignore all alert messages with one click.

tip

If you choose to Ignore the alert and start the migration task, it may cause data inconsistencies and business risks.

For details about the pre-check, refer to Pre-check items.

At the bottom-right of the Pre-check page, click Confirm order.

On the Confirm order configuration wizard page, confirm the configuration information again. Read the Service-Specific Terms for BytePlus Database Products and Services and check I have read and agree to Service-Specific Terms for BytePlus Database Products and Services, and click Create and start a task.

After successfully creating the data migration task, you can return to the DTS console to view the data migration task information on the data migration task list. For more information, refer to Viewing migration tasks.

Step 2: Create a reverse migration task

The reverse migration task provides a rollback solution for your business. After the business is restored, you can immediately switch the business to the original local self-built database if data exceptions occur.

tip

For a reverse migration task, you only need to select incremental migration for the migration type. You can create a reverse migration task according to the following guidance, but do not start the reverse migration task.

Log on to the DTS console.

On the top menu bar, select the project and region.

In the left navigation bar, click Data migration.

On the Migration task list page, click Create task.

On the Create migration task page, locate the Configure source and target database wizard, and configure the following parameters.

Type	Name	Description
None	Task name	Optional. Customize the task name. Naming rules are as follows: Must start with a Chinese character or letter. Must be 64 characters or less. It can contain only Chinese characters, letters, digits, underscores (_), and hyphens (-).
None		Link specification	Select the link specification for the migration task. Compact, Medium and Standard are supported. tip The link specification can not be modified after the task is successfully created. For details on the link specifications, refer to Product specifications.
Source database configuration	Select an existing data source	You can choose whether to use an existing instance as needed: Use existing instances: Click Select an existing data source, then in the Select data source control panel, choose the target region from the Region drop-down list, and select the target data source. Supports selecting data sources by data source name and ID. For methods to create data sources, refer to Data source management. Do not use existing instances: If not using an existing instance, you need to configure the following database instance information.
		Access method	Select Volcano Engine RDS for MySQL.
		Region	Select the region where the target instance is located.
		Cross-Volcano Engine account?	Select whether to transmit data cross-account as needed, with the following options: This account: Selecting this means data transmission occurs only within this account. Cross-account: Selecting this means data transmission occurs between two accounts. tip When transmitting data across accounts, log on to the Database Transmission Service (DTS) console through the account of the destination. Before cross-account data transmission, create and authorize an IAM role in the source root user. For detailed steps, refer to How to authorize users for cross-account data transmission.
		Cross-account ID	Enter the Volcano Engine account ID to which the source database belongs.
		Cross-account roles	Enter the IAM role authorized for DTS to access cross-account resources.
		MySQL instance	Select the target instance of RDS for MySQL from the drop-down list. tip You can also search for the target instance by instance ID or name.
		Node type	Select node types as needed, currently supporting Primary node and Read-only node. tip Select read-only nodes when read-only nodes are created within the instance. For specific steps on creating a read-only node, refer to Read-only node overview.
		MySQL read-only node	Select the target read-only node from the drop-down list. tip When a read-only node is created in the instance and Node type selects Read-only node, this parameter can be configured.
		Database account	Enter the database account of the target instance.
		Database password	Enter the password corresponding to the database account of the target instance.
		Test connection	Click Test connection to verify the connection to the instance. If the test connection fails, modify the configuration based on the failure prompt, and then click Test connection again to verify the connection. The details are as follows: Connection authentication failed. Check if the username and password are correct: When this error prompt appears, verify your username and password. Connection authentication failed, unable to create connection normally, contact customer service: When this error prompt appears, submit a ticket for technical support.
Target database configuration	Select an existing data source	You can choose whether to use an existing instance as needed: Use existing instances: Click Select an existing data source, then in the Select data source control panel, choose the target region from the Region drop-down list, and select the target data source. Supports selecting data sources by data source name and ID. For methods to create data sources, refer to Data source management. Do not use existing instances: If not using an existing instance, you need to configure the following database instance information.
		Instance type	Select MySQL.
		Access method	Select MySQL connected over express network.
		Region	Select the region of the virtual private cloud.
		Host address	Enter the host address of the MySQL instance connected over express network.
		Port	Enter the port of the MySQL instance connected over express network.
		VPC	Select the target VPC from the drop-down list as follows: Direct connect: Select any VPC under the CEN when achieving data connectivity through a dedicated line CEN. VPN connection: Select the VPC bound to the VPN gateway when achieving data connectivity through VPN.
		Subnet	Select a subnet within the VPC from the drop-down list. tip When migrating a MySQL instance connected over express network, you need to add subnet CIDR block access permissions to the allowlist or security group policy on the source end in advance. Click View subnet CIDR blocks to view and copy CIDR blocks.
		Database account	Enter the database account of the target instance.
		Database password	Enter the password corresponding to the database account of the target instance.
		Test connection	Click Test connection to verify the connection to the instance. If the test connection fails, modify the configuration based on the failure prompt, and then click Test connection again to verify the connection. The details are as follows: Connection authentication failed. Check the network: When this error prompt appears, confirm network connectivity. Connection authentication failed. Check the username and password: When this error prompt appears, verify your username and password. Connection authentication failed, unable to create connection normally, contact customer service: When this error prompt appears, submit a ticket to contact technical staff. Invalid IP address: When this error prompt appears, verify the accuracy of the IP address. The Express network requires the subnet to have * available IPs. The current number of available IPs in the subnet is insufficient, and the task can not be created. Check the subnet resources in the VPC: When this error prompt appears, adjust the number of available IPs in the VPC subnet to ensure enough IPs in the target VPC subnet.
None	Project	Optional. Select the affiliated project for the task from the drop-down list. By default, it is under default (default project). You can also click Create new project to create a new project. For more information, refer to Creating a new project. tip To grant sub-user privileges to access resources in a specific project, refer to Modifying project privileges. After a task is created successfully, if you need to change its affiliated project, you can move the resource to another project. For more information, refer to Moving resources to a project. A project is a virtual concept that includes a set of resources, users, and roles. A project allows for a unified view and management of a set of resources, and controls the permissions of users and roles within the project for those resources.
		Tag	(Optional) Click Add tag to add a tag to the instance. Tags can help you categorize cloud resources, control access to them, and allocate bills and costs. A tag is a key-value pair that identifies a cloud resource. You can use tags to categorize resources with the same characteristics from different dimensions, such as purpose or owner, making it easier to filter, aggregate, and manage your cloud resources. For more details about tags, refer to Tag overview. The rules for tag key-value pairs are as follows: Key Supports any language, characters, numbers, spaces, or symbols (_.:/=+-@). Case-sensitive, and the length is 1 to 128 characters. In UTF-8 encoded Unicode format. Keys cannot start with any form of volc:, such as Volc: or VOLC:. (Optional) Value Supports any language, character, digit, space, or symbol (_.:/=+-@). Case-sensitive, and the length is 0 to 256 characters. In UTF-8 encoded Unicode format. tip A maximum of 20 tags can be associated with a task in a single operation. A maximum of 50 tags can be associated with a single task. For a single resource, tag keys must be unique, and each tag key can have only one value.
		Billing method	Currently, only Pay-as-you-go is supported. No selection is required. tip For detailed billing information, refer to Billing instructions.

Click Next step: configure migration object.

On the Configure migration object wizard page, configure the related parameter information as shown in the table below.

Name	Description
Migration type	For reverse migration tasks, you only need to migrate the newly added data in the cloud to the local database as storage backup. Therefore, you only need to select Incremental migration.
Migration starting point	Set to pull Binlog logs from a specified position or timestamp. The values are as follows: System default: The default is the task start time. Specify GTID: Enter the specified GTID in the input box, formatted as source_id:transaction_id. Set GTID_EXECUTED: Enter the specified GTID_EXECUTED in the input box, formatted as source_id:transaction_id. If multiple exist, separate them with commas (,). For how to obtain the instance's GTID_EXECUTED, refer to How to obtain the GTID_EXECUTED of the instance. Specify timestamp: Click the input box to select a date, click Select time to set the time point, then click OK.
Whether to enable foreign key check?	Select whether to enable foreign key check as needed. When enabled, the tool supports migrating cascading updates and deletes of foreign keys from the source, ensuring data integrity and consistency throughout the migration.
Migration object	In the Migration object area, check the objects selected in the forward migration task. You can use Normal search and Global search to find target objects.
Error retry time	If a migration task fails due to a disconnection between the source and target databases, the system immediately retries connecting to them multiple times within the specified time. Value range: 600 - 86400, in seconds (s). The default value is 600 seconds.

Click Save.

warning

To create a reverse migration task, simply click Save without starting the reverse migration task.

Step 3: Switch business to cloud database

When the forward task completes full migration and schema migration and enters the incremental migration stage, you can complete the service cut-over operation according to the following configurations.

(Optional) Log in to the source database and execute the following command according to the database type to view the session information, and ensure that no new sessions perform write operations.

MySQL & veDB MySQL

Redis

MongoDB

PostgreSQL

show processlist;

(Optional) Before switching services, you can perform data verification to verify whether the source and destination data are consistent.

You need to create a full validation task and a schema verification task. For details, refer to Creating a data verification task.

Switch the service to the cloud database.

Suspend business writes to the local self-built database on the source end.

Switch the service to the cloud database.

Step 4: Pause the forward migration task and start the reverse migration task

Pause the forward migration task.Task For details, refer to Pausing a migration task.

tip

When the migration task is suspended, do not start the task at will; otherwise, data inconsistency may occur.

Start the reverse migration task. For details, refer to Starting a migration task.

Start writing cloud business.

Test business functions.

Step 5: (optional) Service rollback

If an exception occurs in the cloud business, refer to the following operation prompts to reduce the impact of data migration on the business.

Pause the business and prohibit the writing of new data.

Switch the service to the source on-premises self-built database.

Resume writing business data.

Last updated: 2026.09.02 16:10:46