SQL Server migration on AWS - ApsaraDB RDS - Alibaba Cloud Documentation Center

Prerequisites

You have created a destination RDS SQL Server instance with more storage space than the source database.
You have connected the Amazon RDS for SQL Server database to Alibaba Cloud so that DTS can connect to the source database.
The source database version must meet the following requirements:
- enterprise edition: SQL Server 2008 or later.
- standard edition: SQL Server 2016 SP1 or later.
- SQL Server 2017 (standard edition and enterprise edition): We recommend upgrading to a later version.

Precautions

Review these key precautions before migration. Ignoring them can cause the task to fail or report errors:

Database count limit: A single migration task supports a maximum of 10 databases. Exceeding this limit can cause stability and performance issues.
Table count limit: When a task includes incremental migration, it can synchronize a maximum of 1,000 tables from the source database. Otherwise, task delays or instability may occur.
Source database operation limits: During the schema migration and full migration phases, do not perform DDL operations, such as modifying database or table schemas. Otherwise, the task will fail.
CDC-related limits: If CDC is enabled for tables in the source database and the data in a single field exceeds 64 KB, you must run theEXEC sp_configure 'max text repl size', -1; command to adjust the configuration. Otherwise, the task may fail.
Table schema requirements: Tables to be migrated must have a primary key or a unique constraint to ensure each row is unique. Otherwise, data duplication may occur in the target database.
Foreign keys and triggers: For incremental data migration tasks, you must disable all triggers and foreign keys in the target database. Otherwise, the task may fail or data loss may occur.
Database naming conventions: If the name of a database to be migrated does not comply with the naming conventions of RDS SQL Server, you must manually create the database in RDS SQL Server. Otherwise, the task may not run correctly.
Data log retention period: For incremental migration tasks, the source database logs must be retained for more than 24 hours. For tasks that include both full and incremental migration, data logs must be retained for at least 7 days. Otherwise, the task may fail or data inconsistencies may occur.

Limits and precautions

Note

DTS does not migrate foreign keys. As a result, cascade operations such as cascade delete in the source database are not replicated in the destination database.

Type	Description
Source database limits	The source database has the following version limits: If the source database is Enterprise Edition, its version must be 2008 or later. If the source database is Standard Edition, its version must be 2016 SP1 or later. If the source database is SQL Server 2017 (Standard or Enterprise Edition), we recommend that you upgrade the version. The server that hosts the source database requires sufficient outbound bandwidth. Insufficient bandwidth reduces data migration speed. Tables to be migrated must have a primary key or unique constraint. Otherwise, duplicate data may exist in the destination database. A single migration task can migrate a maximum of 10 databases. Split the migration into multiple tasks if you need to migrate more. If you configure a task to migrate specific objects instead of an entire database, you cannot migrate objects that have the same table name but different schema names to the same destination database within a single task. For an incremental data migration task, you must retain the transaction logs of the source database for at least 24 hours. For a task that includes both full and incremental data migration, retain logs for at least seven days. You can change the retention period to at least 24 hours after full data migration is complete. Otherwise, the DTS task may fail. In extreme cases, data inconsistency or loss may occur. Issues caused by insufficient log retention are not covered by the DTS Service Level Agreement (SLA). Limits on operations on the source database: During the schema migration and full data migration phases, do not perform DDL operations that change the database or table structure. Otherwise, the data migration task fails. If you perform only full data migration, do not write new data to the source instance. Otherwise, data will become inconsistent between the source and destination databases. To ensure data consistency, select all three migration types: schema migration, full data migration, and incremental data migration. The source database cannot be a read-only instance. If you use the `sp_rename` command to rename objects such as stored procedures before the schema migration task runs, the task may not work as expected or may fail. Note Use the `ALTER` command to rename database objects. During full data migration, enable the `READ_COMMITTED_SNAPSHOT` parameter for the source database to prevent shared lock contention from affecting data writes. Otherwise, data inconsistency or task failure may occur. Issues caused by not enabling this parameter are not covered by the DTS SLA.
Other limits	DTS does not support migrating the following data types: CURSOR, ROWVERSION, SQL_VARIANT, HIERARCHYID, POLYGON, GEOMETRY, and GEOGRAPHY. To migrate triggers from the source database, the database account used for the migration task must have Owner permissions on the destination database. If data cannot be written to a column of the TIMESTAMP data type in the destination database, DTS does not support full or incremental data migration. This may lead to data inconsistency or task failure. The precheck module for a DTS incremental data migration task enables CDC in the source database. During this process, the SQL Server engine's internal limitations may cause temporary table locking in the source database. An incremental data migration task migrates incremental data by polling CDC instances. Therefore, the following limits apply: DTS polls the CDC instance of each table to obtain incremental data. To prevent high latency and instability, do not synchronize more than 1,000 tables. By default, the CDC component stores incremental data for three days. Adjust the retention period by running the `exec console.sys.sp_cdc_change_job @job_type = 'cleanup', @retention= <time>;` command. Note `<time>` specifies the retention period in minutes. If the average number of daily incremental SQL changes for a single table exceeds 10 million, set `<time>` to 1440. Consecutive column add or drop operations are not supported (more than two ADD COLUMN or DROP COLUMN DDL operations within 1 minute). Otherwise, the task may fail. Do not modify the CDC instances of the source database. Otherwise, the migration task may fail or data loss may occur. Migrating multiple databases and tables increases the risk of stability and performance issues. Incremental data migration has a latency of approximately 10 seconds. If you migrate data across different SQL Server versions, verify compatibility in advance. For a migration task that includes incremental data migration, do not rebuild indexes, and disable any active triggers and foreign keys in the destination database. Otherwise, the task may fail or result in data loss. Note Changes related to the primary key are not supported for tables for which CDC is enabled. If the number of CDC-enabled tables in a single migration task exceeds 1,000 (or exceeds the value configured for The maximum number of tables for which CDC is enabled that DTS supports.), the precheck fails. If a task includes incremental migration and a single field in a CDC-enabled table to be written contains more than 64 KB of data, run the `exec sp_configure 'max text repl size', -1;` command to adjust the source database configuration in advance. Note By default, a CDC job can process a maximum data size of 64 KB for a single field. DTS automatically creates databases in RDS SQL Server. If the name of the database to be migrated does not conform to the naming conventions of RDS SQL Server, you must create the database in RDS SQL Server before you configure the migration task. For more information, see Create a database. To ensure accurate latency for incremental data migration, when you use incremental synchronization based on log parsing, DTS creates the dts_cdc_sync_ddl trigger, the dts_sync_progress heartbeat table, and the dts_cdc_ddl_history DDL history table in the source database. When you use hybrid incremental synchronization mode, DTS creates the same objects and also enables database-level CDC and CDC for some tables. For tables where CDC is enabled, we recommend that the rate of data changes does not exceed 1,000 RPS. Before migrating data, evaluate the performance of the source and destination databases and perform migration during off-peak hours. During full data migration, DTS consumes read and write resources on both databases, which may increase their load. During full data migration, concurrent INSERT operations can cause fragmentation in the destination tables, so tables may require more storage space in the destination database than in the source instance after migration. Verify that the migration precision that DTS uses for FLOAT and DOUBLE data types meets your business requirements. DTS uses the `ROUND(COLUMN,PRECISION)` function to read values from these columns. If a precision is not explicitly defined, DTS migrates FLOAT values with a precision of 38 digits and DOUBLE values with a precision of 308 digits. DTS attempts to resume a failed task for up to seven days. Before you switch your business workloads to the destination instance, you must end or release the task. Alternatively, revoke the write permissions of the DTS account on the destination instance by using the `revoke` command to prevent automatic resumption from overwriting destination data. When multiple migration instances use the same source SQL Server database, their incremental data collection modules operate independently. If a task fails, DTS support staff will attempt to restore it within eight hours. During restoration, they may restart the task or adjust its parameters. Note Only DTS task parameters are modified—not database parameters. Parameters that may be adjusted include those listed in Modify instance parameters. SQL Server is a commercial, closed-source database whose log format can cause unavoidable issues during incremental CDC and parsing in DTS. Before enabling DTS for incremental synchronization from a SQL Server source in a production environment, perform comprehensive proof-of-concept (POC) testing that covers all business change scenarios, schema adjustments, and peak-load stress tests. Consistency between your production environment logic and the POC phase is essential for stable DTS operations. Partial transaction rollbacks on the source are not supported during incremental data migration, and some rollback operations may be missed.

Billing

Migration type	Instance configuration fee	Internet traffic fee
Schema migration and full data migration	Free of charge.	When the Access Method parameter of the destination database is set to Public IP Address, you are charged for Internet traffic. For more information, see Billing overview.
Incremental data migration	Charged. For more information, see Billing overview.

Database account permissions

To complete the data migration, ensure the source and target database accounts have the following permissions:

Amazon RDS for SQL Server

Schema migration: Requires the SELECT permission.
Full migration: Requires SELECT permission.
Incremental migration: Requires the dbower permission (to enable the CDC feature).

Note

A high-privilege account for Amazon RDS for SQL Server meets these requirements. For more information, see the AWS platform documentation or contact technical support.

RDS SQL Server

Structure migration, full migration, and incremental migration require read and write permissions.

Note

In the RDS console, you can create a standard or high-privilege account and modify account permissions.

Procedure

The one-stop cloud migration feature in the RDS console migrates the schema, full data, and incremental data by default, providing a simple and convenient process. The data migration feature in the Data Transmission Service (DTS) console supports custom migration types and more advanced parameter configurations, making the configuration process more complex.

Method 1: RDS one-stop migration

Go to the RDS Instances page. At the top of the page, select the region of your target instance, and then click the ID of the target instance.
In the left navigation bar, click Data Migration and Synchronization. The Data Migration page opens.

Click One-stop Cloud Migration, and configure the source and destination database information.

Category	Parameter	Description
N/A	Task Name	Enter a descriptive name for the task for easy identification. The name does not have to be unique. You can also use the system-generated task name.
Source Database	Database Type	The default value is SQL Server. No selection is required.
	Type	Select AWS.
	Access Method	Select Public IP Address or Express Connect, VPN Gateway, or Smart Access Gateway based on how your Amazon RDS for SQL Server instance connects to Alibaba Cloud. This example uses Express Connect, VPN Gateway, or Smart Access Gateway.
	Instance Region	When Access Method is set to Public IP Address: Select the region where the Amazon RDS for SQL Server is located. Note If the region of your Amazon RDS for SQL Server instance is not listed, select the nearest one. When Access Method is set to Express Connect, VPN Gateway, or Smart Access Gateway, select the region where the Alibaba Cloud Virtual Private Cloud (VPC) used to access Amazon RDS for SQL Server is located.
	Connected VPC	Select the ID of the Alibaba Cloud Virtual Private Cloud (VPC) to which your Amazon RDS for SQL Server instance is connected. Note This setting is available only when the Access Method is set to Express Connect, VPN Gateway, or Smart Access Gateway.
	Domain Name or IP	Enter the domain name or IP address of the Amazon RDS for SQL Server instance. Note A domain name is recommended.
	Port Number	Enter the service port of the Amazon RDS for SQL Server instance.
	Database Account	Enter the database account of the Amazon RDS for SQL Server instance. For the required permissions, see Database account permissions.
	Database Password	Enter the password for the database account.
	Encryption	If the source database does not use SSL encryption, select Non-encrypted. If SSL encryption is enabled for the source database, select SSL-encrypted. DTS trusts the server certificate by default.
Destination Database	Database Type	Defaults to SQL Server. No selection is required.
	Access Method	The default is Alibaba Cloud Instance. No selection is required.
	Instance Region	The region where the RDS for SQL Server instance is located. This cannot be changed.
	Instance ID	The ID of the RDS for SQL Server instance. This cannot be changed.
	Database Account	Enter the database account for the current RDS for SQL Server instance and ensure that the account has the required permissions.
	Database Password	Enter the password for the database account.
	Encryption	If SSL encryption is not enabled for the destination database, select Non-encrypted. If SSL encryption is enabled for the target database, select SSL-encrypted. DTS trusts the server certificate by default.

After completing the configuration, click Test Connection to Proceed at the bottom of the page.

Important
Add the DTS server IP addresses shown in the pop-up window to the allowlist of your Amazon RDS for SQL Server instance. Adding DTS IP addresses may pose security risks. Confirm this action and take necessary protective measures, such as using strong passwords and restricting port access.
The system evaluates your source database and presents the following two cloud migration plans.
- For the Full and incremental data migration plan, click Configure Objects at the bottom of the page to proceed to the next step.
- If you select the Data migration using full and incremental backups cloud migration solution, you do not need to proceed to the next step.
  
  Note
  You can click View Migration Documentation at the bottom of the page to view the corresponding cloud migration steps.

On the Configure Objects page, configure the objects to be migrated.

Parameter	Description
Method to Migrate Triggers in Source Database	During incremental data migration, data inconsistency between the source and destination databases can occur if triggers are migrated to the destination database prematurely. You can select a method to migrate triggers based on your actual situation. We recommend that you select Manual Migration. For more information, see Configure the method for synchronizing or migrating triggers. Note If the objects you are migrating do not involve triggers, you do not need to configure this parameter. You can keep the default setting.
Source Objects	In the Source Objects box, click the objects to migrate, and then click to move them to the Selected Objects box. Note You can select objects at the database, table, or column level. If you select tables or columns, other objects such as views, triggers, and stored procedures are not migrated to the destination database.
Selected Objects	To change the name of a migration object in the destination instance, right-click the migration object in Selected Objects to modify it. For instructions, see Database, Table, and Column Name Mapping. To remove a selected migration object, in the Selected Objects box, click the object, and then click to move it to the Source Objects box. Note If you use object name mapping, the migration of dependent objects might fail. To set a WHERE condition to filter data, right-click the table to be migrated in the Selected Objects section and set the filter condition in the dialog box that appears. For more information, see Set Filter Conditions. To select SQL operations for migration at the database or table level, right-click the object to be migrated in the Selected Objects area, and in the pop-up dialog box, select the required SQL operations.

Optional: Configure advanced settings.

You can expand the advanced configuration section to configure advanced parameters.

Parameter	Description
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.
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.
Data Verification Mode	Full data verification consumes database read resources. If you select Full Data Verification, you must also configure the Maximum number of rows of data read per second by full verification (RPS) and Maximum amount of data read per second by full verification (MBps) settings to limit the rate of the full validation task and reduce the pressure on the database. Note A value of 0 indicates no limit. If both Maximum number of rows of data read per second by full verification (RPS) and Maximum amount of data read per second by full verification (MBps) are set to 0, the speed is unlimited.

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

Purchase the 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.

Method 2: DTS cloud migration

Go to the Data Transmission Service (DTS) console.
In the left navigation bar, click Data Migration, and select the region at the top.

Click Create Task and configure the source and destination databases.

Category	Parameter	Description
N/A	Task Name	Enter a descriptive name for the task for easy identification. The name does not have to be unique. You can also use the system-generated task name.
Source Database	Select Existing Connection	If you have already entered the source database information on the DTS Data connection management page, you can select the database here. This saves you from entering the source database information again.
	Database Type	Select SQL Server.
	Access Method	Select Public IP Address or Express Connect, VPN Gateway, or Smart Access Gateway based on the method that is used to connect Amazon RDS for SQL Server to Alibaba Cloud. In this example, Express Connect, VPN Gateway, or Smart Access Gateway is selected.
	Instance Region	When Access Method is set to Public IP Address, select the region of the Amazon RDS for SQL Server instance. Note If the region of your Amazon RDS for SQL Server instance is not listed, select the nearest one. When Access Method is set to Express Connect, VPN Gateway, or Smart Access Gateway, select the region of the Alibaba Cloud Virtual Private Cloud (VPC) that is used to connect to Amazon RDS for SQL Server.
	Replicate Data Across Alibaba Cloud Accounts	In this example, a database instance under the current Alibaba Cloud account is used. Select No. Note This setting is available only when the Access Method is set to Express Connect, VPN Gateway, or Smart Access Gateway.
	Connected VPC	Select the ID of the Alibaba Cloud Virtual Private Cloud (VPC) to which your Amazon RDS for SQL Server instance is connected. Note This setting is available only when the Access Method is set to Express Connect, VPN Gateway, or Smart Access Gateway.
	Domain Name or IP	Enter the domain name or IP address of the Amazon RDS for SQL Server instance. Note A domain name is recommended.
	Port Number	Enter the service port of the Amazon RDS for SQL Server instance.
	Database Account	Enter the database account for the Amazon RDS for SQL Server instance, and ensure that the account has the required permissions.
	Database Password	Enter the password for the database account.
	Encryption	If the source database does not use SSL encryption, select Non-encrypted. If SSL encryption is enabled for the source database, select SSL-encrypted. DTS trusts the server certificate by default.
Destination Database	Select Existing Connection	If you have already entered the destination database information on the DTS Data connection management page, you can select the database here. This saves you from entering the destination database information again.
	Database Type	Select SQL Server.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the destination RDS for SQL Server instance resides.
	Instance ID	Select the ID of the destination RDS for SQL Server instance.
	Database Account	Enter the database account of the destination RDS for SQL Server instance, and ensure that the account has the required permissions.
	Database Password	Enter the password for the database account.
	Encryption	If SSL encryption is not enabled for the target database, select Non-encrypted. If SSL encryption is enabled for the destination database, select SSL-encrypted. DTS trusts the server certificate by default.

After you complete the configuration, click Test Connection to Proceed at the bottom of the page.

Important
Add the DTS server IP addresses shown in the pop-up window to the allowlist of your Amazon RDS for SQL Server instance. Adding DTS IP addresses may pose security risks. Confirm this action and take necessary protective measures, such as using strong passwords and restricting port access.

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	During incremental data migration, data inconsistency between the source and destination databases can occur if triggers are migrated to the destination database prematurely. You can select a method to migrate triggers based on your actual situation. We recommend that you select Manual Migration. For more information, see Configure the method for synchronizing or migrating triggers. Note You can configure this setting only if you select both Schema Migration and Incremental Data Migration for Migration Types. If the objects you are migrating do not involve triggers, you do not need to configure this parameter. You can keep the default setting.
SQL Server Incremental Synchronization Mode	Select Polling and querying CDC instances for incremental synchronization. Note This parameter is available only if your Migration Types selection includes Incremental Data Migration.
The maximum number of tables for which CDC is enabled that DTS supports.	Keep the default value for this example.
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	In the Source Objects box, click the objects to migrate, and then click to move them to the Selected Objects box. Note You can select objects at the database, table, or column level. If you select tables or columns, other objects such as views, triggers, and stored procedures are not migrated to the destination database.
Selected Objects	To change the name of a migration object in the destination instance, right-click the migration object in Selected Objects to modify it. For instructions, see Database, Table, and Column Name Mapping. To remove a selected migration object, in the Selected Objects box, click the object, and then click to move it to the Source Objects box. Note If you use object name mapping, the migration of dependent objects might fail. To set a WHERE condition to filter data, right-click the table to be migrated in the Selected Objects section and set the filter condition in the dialog box that appears. For more information, see Set Filter Conditions. To select SQL operations for migration at the database or table level, right-click the object to be migrated in the Selected Objects area, and in the pop-up dialog box, select the required SQL operations.

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.
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 as needed. No selection is needed for this example.
Configure ETL	Choose whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: Enables the ETL feature. Enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: Disables 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 Verification to configure the data verification task.

If you need to use the data verification feature, refer to Configure data verification for instructions.

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.

Appendix 1: SQL operations for incremental migration

DML operations

INSERT, UPDATE, DELETE

Note

Incremental migration does not support UPDATE statements that only update large objects.

DDL operations

CREATE TABLE

Note
CREATE TABLE statements that include a partition or a function in the table definition are not supported.
ALTER TABLE

Only ADD COLUMN and DROP COLUMN are supported.
DROP TABLE
CREATE INDEX, DROP INDEX

Note

Transactional DDL is not supported. For example, a single SQL statement adding multiple columns or containing both DDL and DML operations may cause data loss.
DDL that contains user-defined types is not supported.
Online DDL is not supported.
DDL that uses a reserved keyword as an attribute name is not supported.
DDL executed by a system stored procedure is not supported.
TRUNCATE TABLE is not supported.

Appendix 2: Objects supported in schema migration

Supported object types: table, view, trigger, synonym, SQL stored procedure, SQL function, plan guide, user-defined type, rule, default, sequence.

Not supported: assemblies, service brokers, full-text indexes, full-text catalogs, distributed schemas, distributed functions, CLR stored procedures, CLR scalar-valued functions, CLR table-valued functions, internal tables, systems, aggregate functions.

FAQ

Can I select verification objects for ApsaraDB RDS One-Stop Cloud Migration?

No. By default, the verification objects are the same as the migration objects.
How is full data verification performed for ApsaraDB RDS One-Stop Cloud Migration?

The process uses HASH verification at a 100% sampling ratio.
What is the benchmark for full data verification in ApsaraDB RDS One-Stop Cloud Migration?

It uses the union of data from the source and destination databases as the benchmark to verify data consistency.