Migrate data from a self-managed SQL Server database to an ApsaraDB RDS for PostgreSQL instance-Data Transmission Service(DTS)-阿里云帮助中心

Prerequisites

The CIDR blocks of DTS servers are added to the security settings (such as security group rules, firewall rules, or allowlists) of the self-managed SQL Server database to allow access from DTS servers.
A destination ApsaraDB RDS for PostgreSQL instance whose storage space is larger than the space used by the source SQL Server database is created. For information about how to create an instance, see Quickly create an RDS PostgreSQL instance.
Note
For the versions supported by the source and destination databases, see Migration scenarios.
A database used to receive data is created in the destination ApsaraDB RDS for PostgreSQL instance. For information about how to create a database, see Create a database.
If the source instance has any of the following conditions, we recommend that you split the migration into multiple tasks:
- The schema of the data to be migrated has more than one namespace.
- Log backups are performed more than once per hour for a single database.
- More than 100 Data Definition Language (DDL) operations are performed per hour on a single database.
- The log generation rate for a single database exceeds 20 MB/s.
- You must enable change data capture (CDC) on more than 1,000 tables.

Usage notes

Note

DTS migrates foreign keys during schema migration.
During full and incremental data migration, DTS temporarily disables constraint checks and foreign key cascades at the session level. Cascade updates or deletes on the source database while the task runs may cause data inconsistency.

Type	Description
Source database limits	The source database server must have sufficient outbound bandwidth. Insufficient bandwidth reduces data migration speed. The tables to be migrated must have a primary key or unique constraint, and the columns in the key or constraint must be unique. Otherwise, data duplication may occur in the destination database. If you select specific tables for migration and need to edit them (for example, map table or column names), a single migration task can migrate a maximum of 1,000 tables. If you exceed this limit, the task fails upon submission. Split the tables into multiple tasks or configure a task to migrate the entire database. A single migration task supports a maximum of 10 databases. Exceeding this limit may cause stability and performance issues. Split the migration into multiple tasks if needed. 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. If you perform incremental data migration, the transaction logs must meet the following requirements: Transaction logging must be enabled, the backup mode must be set to Full, and a full physical backup must have been successfully performed. For incremental-only data migration, Data Transmission Service (DTS) requires retaining source database transaction logs for more than 24 hours. If a task includes both full and incremental data migration, retain logs for at least seven days. After full data migration is complete, you can reduce the retention period to more than 24 hours. Otherwise, the DTS task may fail due to unavailable transaction logs. 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). If you enable CDC (change data capture) for the source tables to be migrated, they must meet the following conditions. Otherwise, the precheck will fail. The value of the `srvname` field in the `sys.sysservers` view must be the same as the return value of the `SERVERPROPERTY` function. If the source database is a self-managed SQL Server, the database owner must be `sa`. If the source database is an ApsaraDB RDS for SQL Server instance, the database owner must be `sqlsa`. If the source database is Enterprise Edition, it must be SQL Server 2008 or later. If the source database is Standard Edition, it must be SQL Server 2016 SP1 or later. If the source database is SQL Server 2017 (Standard or Enterprise Edition), upgrade it to a later version. DTS uses the fn_log function to obtain logs from the source database. This function has performance bottlenecks, so do not clear source database logs prematurely. Otherwise, the DTS task may fail. Limits on operations in 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 will fail. If you perform only full data migration, do not write new data to the source instance. Otherwise, data in the source and destination databases becomes inconsistent. To ensure real-time data consistency, select Schema Migration, Full Data Migration, and Incremental Data Migration. If the source database is a read-only instance, DTS does not migrate DDL operations. If the source database is an Azure SQL Database, a migration instance can migrate only one database. If the source database is an ApsaraDB RDS for SQL Server instance and the migration task includes incremental data migration, ensure that Transparent Data Encryption (TDE) is disabled for task stability. For more information, see Disable TDE. 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. In hybrid log-based parsing mode, the source database does not support consecutive column add or drop operations with an interval of less than 10 minutes. For example, if you run the following SQL statements consecutively, the task will fail. `ALTER TABLE test_table DROP COLUMN Flag; ALTER TABLE test_table ADD Remark nvarchar(50) not null default('');` If the source database is an ApsaraDB RDS for SQL Server instance that runs the Web edition, set SQL Server Incremental Synchronization Mode to Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported) when you configure the task. 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	Migration is supported for basic data types only, but not for data of the CURSOR, ROWVERSION, SQL_VARIANT, HIERARCHYID, POLYGON, GEOMETRY, or GEOGRAPHY types, or for user-defined types that are created by using the `CREATE TYPE` command. Important This scenario is a heterogeneous database migration. Mismatched data types can cause task failures or data loss. Carefully assess the impact of data type mappings on your business. For more information, see Data type mappings between heterogeneous databases. You can select migration objects only at the table level. All selected tables must belong to the same schema. Otherwise, data inconsistency or task failure may occur. If you set Configure Objects to SQL Server Incremental Synchronization Mode in the Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported) step, the tables to be migrated must have a clustered index that includes the primary key column. DTS does not support migrating heap tables, tables without primary keys, compressed tables, tables with computed columns, or tables with sparse columns in this mode. These limitations do not apply in hybrid log-based parsing mode. Note For information about how to view table details, see How do I view information about heap tables, tables without primary keys, compressed tables, tables with computed columns, and tables with sparse columns in SQL Server? If you set Configure Objects to SQL Server Incremental Synchronization Mode in the Log-based Parsing for Non-heap Tables and CDC-based Incremental Synchronization for Heap Tables (Hybrid Log-based Parsing) step, the following limits also apply: DTS relies on the CDC component for incremental migration. Ensure that the CDC job in the source database is running as expected. Otherwise, the DTS task will fail. 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. In a single migration task, enable CDC for no more than 1,000 tables. Otherwise, the task may experience high latency or become unstable. 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. If you set Configure Objects to SQL Server Incremental Synchronization Mode in the Polling and querying CDC instances for incremental synchronization step, the following limits also apply: The source database account used by the DTS instance must have the permissions to enable CDC. An account with the `sysadmin` role is required to enable database-level CDC. A privileged account is required to enable table-level CDC. Note The most privileged account (server administrator) provided by the Azure SQL Database console meets the requirements. For databases purchased based on the vCore model, CDC can be enabled for all specifications. For databases purchased based on the DTU model, CDC can be enabled only for service tiers of S3 or higher. The privileged account of an Amazon RDS for SQL Server instance meets the requirements and supports enabling database-level CDC via stored procedures. CDC cannot be enabled for tables that have a clustered columnstore index. 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. DTS obtains incremental data by polling and querying the CDC instance of each table in the source database. Migrate no more than 1,000 tables from the source database. Otherwise, the task may experience high latency or become unstable. 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 one minute). Otherwise, the task may fail. Do not modify the CDC instances of the source database. Otherwise, the data migration task may fail or data loss may occur. To ensure accurate latency reporting for incremental data migration, DTS creates objects in the source database. In the log-based parsing mode, DTS creates a `dts_cdc_sync_ddl` trigger, a `dts_sync_progress` heartbeat table, and a `dts_cdc_ddl_history` DDL storage table. In the hybrid log-based parsing mode, DTS creates the same objects and also enables database-level and table-level CDC. For tables where CDC is enabled, the rate of data changes should not exceed 1,000 rows per second (RPS). During a full migration, DTS consumes read and write resources on both the source and destination databases, which may increase the database load. Before starting, assess the performance of both databases and run the migration during off-peak hours, for example, when CPU load is below 30%. During a full migration, concurrent INSERT operations can cause fragmentation in the destination tables, so tables in the destination database might use more storage space than those in the source database after migration. DTS attempts to resume a failed task for up to seven days. Before switching your business workloads to the destination instance, end or release the migration task. Alternatively, revoke the write permissions of the DTS account on the destination instance by using the `revoke` command to prevent a resumed task from overwriting destination data. If a migration task includes incremental data migration, you cannot perform re-indexing operations. This may cause the task to fail or result in data loss. Note You cannot modify the primary key of a table for which CDC is enabled. If the number of CDC-enabled tables in a single migration task exceeds the value set in the The maximum number of tables for which CDC is enabled that DTS supports. parameter, 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. 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. During incremental migration, DTS does not support partial transaction rollbacks in the source database, which may cause them to be missed.
Special cases	If the source is an ApsaraDB RDS for SQL Server instance, DTS creates a system account named `rdsdt_dtsacct` on the instance for data migration. Do not delete this account or change its password while the task is running. Otherwise, the task may fail. For more information, see System accounts.

Billing

Migration type	Link configuration fee	Internet traffic fee
Schema migration and full data migration	Free of charge.	Free of charge in this example. Note You are charged when the Access Method of the destination database instance is Public IP Address. For more information, see Billing overview.
Incremental data migration	Charged. For more information, see Billing overview.

SQL operations that support incremental migration

Operation type	SQL statements
DML	INSERT, UPDATE, DELETE Note UPDATE statements that update only large fields are not supported.

Permissions required for database accounts

Database	Required permissions	Account creation and authorization methods
Source self-managed SQL Server	sysadmin permission.	CREATE USER and User permission management
Destination ApsaraDB RDS for PostgreSQL instance	Owner permission (authorization account) of the destination database.	Create an account and Create a database.

Prerequisites

Note

To perform an incremental migration, you must configure log settings and create clustered indexes on your self-managed SQL Server database before configuring the data migration task.

Important

If you need to migrate multiple databases, you must repeat steps 1 through 3 for each database. Failure to do so may result in data inconsistency.

Run the following command on your self-managed SQL Server database to change the recovery model of the source database to the full recovery model.
```
use master;
GO
ALTER DATABASE <database_name> SET RECOVERY FULL WITH ROLLBACK IMMEDIATE;
GO
```
Parameters:

<database_name>: The name of the source database.

Example:
```
use master;
GO
ALTER DATABASE mytestdata SET RECOVERY FULL WITH ROLLBACK IMMEDIATE;
GO
```
Run the following command to create a logical backup of the source database. You can skip this step if a logical backup already exists.
```
BACKUP DATABASE <database_name> TO DISK='<physical_backup_device_name>';
GO
```
Parameters:
- <database_name>: The name of the source database.
- <physical_backup_device_name>: The path and filename for the backup file.
Example:
```
BACKUP DATABASE mytestdata TO DISK='D:\backup\dbdata.bak';
GO
```
Run the following command to back up the transaction log of the source database.
```
BACKUP LOG <database_name> to DISK='<physical_backup_device_name>' WITH init;
GO
```
Parameters:
- <database_name>: The name of the source database.
- <physical_backup_device_name>: The path and filename for the backup file.
Example:
```
BACKUP LOG mytestdata TO DISK='D:\backup\dblog.bak' WITH init;
GO
```

Procedure

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.

Category	Parameter	Description
None	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 Existing Connection	To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured. Note In the DMS console, this parameter is named Select a DMS database instance.. If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.
	Database Type	Select SQL Server.
	Access Method	Select this based on the deployment location of the source database. In this example, select Public IP Address. Note If you select a different access method for a self-managed database, you must complete corresponding preparations. For more information, see Preparation overview.
	Instance Region	Select the region to which the source SQL Server database belongs.
	Domain Name or IP	Enter the access address of the source SQL Server database.
	Port Number	Enter the service port of the source SQL Server database. The default port is 1433.
	Database Account	Enter the account of the source SQL Server database. For information about the required permissions, see Permissions required for database accounts.
	Database Password	Enter the password for the database account.
	Encryption	Select Non-encrypted or SSL-encrypted based on your business requirements. If SSL encryption is disabled for the source database, select Non-encrypted. If SSL encryption is enabled for the source database, select SSL-encrypted. By default, DTS trusts the server certificate.
Destination Database	Select Existing Connection	To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured. Note In the DMS console, this parameter is named Select a DMS database instance.. If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.
	Database Type	Select PostgreSQL.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region of the destination ApsaraDB RDS for PostgreSQL instance.
	Instance ID	Select the ID of the destination ApsaraDB RDS for PostgreSQL instance.
	Database Name	Enter the name of the database that is used to receive data in the destination ApsaraDB RDS for PostgreSQL instance.
	Database Account	Enter the database account of the destination ApsaraDB RDS for PostgreSQL instance. For information about the required permissions, see Permissions required for database accounts.
	Database Password	Enter the password for the database account.
	Encryption	Specifies whether to encrypt the connection to the source database. You can configure this parameter based on your business requirements. In this example, Non-encrypted is selected. If you want to establish an SSL-encrypted connection to the source database, perform the following steps: Select SSL-encrypted, upload CA Certificate, Client Certificate, and Private Key of Client Certificate as needed, and then specify Private Key Password of Client Certificate. Note If you set Encryption to SSL-encrypted for a self-managed PostgreSQL database, you must upload CA Certificate. If you want to use the client certificate, you must upload Client Certificate and Private Key of Client Certificate and specify Private Key Password of Client Certificate. For information about how to configure SSL encryption for an ApsaraDB RDS for PostgreSQL instance, see SSL encryption.

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.
SQL Server Incremental Synchronization Mode	Log-based Parsing for Non-heap Tables and CDC-based Incremental Synchronization for Heap Tables (Hybrid Log-based Parsing): Advantages: Supports scenarios that involve source heap tables, tables without primary keys, compressed tables, or tables with computed columns. Provides high link stability. This mode can obtain complete DDL statements and supports a wide range of DDL scenarios. Disadvantages: DTS creates the `dts_cdc_sync_ddl` trigger, the `dts_sync_progress` heartbeat table, and the `dts_cdc_ddl_history` DDL storage table in the source database. It also enables database-level CDC and CDC for some tables. You cannot execute `SELECT INTO`, `TRUNCATE`, or `RENAME COLUMN` statements on tables with CDC enabled in the source database. You cannot manually delete triggers created by DTS in the source database. Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported): Advantage: This mode is non-intrusive to the source database. Disadvantage: This mode does not support scenarios that involve source heap tables, tables without primary keys, compressed tables, or tables with computed columns. Polling and querying CDC instances for incremental synchronization: Advantages: Supports full and incremental migration when the source database is Amazon RDS for SQL Server, Azure SQL Database, Azure SQL Managed Instance, Azure SQL Server on Virtual Machine, or Google Cloud SQL for SQL Server. This mode uses the native CDC component of SQL Server to obtain incremental data, which improves the stability of incremental migration and reduces network bandwidth usage. Disadvantages: The source database account used by the DTS instance must have the permissions to enable CDC. Incremental data migration has a latency of about 10 seconds. When you migrate multiple tables across multiple databases, you may encounter stability and performance issues. Note This parameter is available only when the selection for Migration Types includes Incremental Data Migration.
The maximum number of tables for which CDC is enabled that DTS supports.	You can set a limit on the number of CDC-enabled tables for the current migration instance based on your business requirements. The default value is 1,000. Note This parameter is not available if you set SQL Server Incremental Synchronization Mode to Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported).
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 pane, click the tables that you want to migrate and click to move them to the Selected Objects pane. Important The granularity of objects that can be selected for migration is tables, and all tables to be migrated must belong to the same schema. Otherwise, data inconsistency or task failure may occur.
Selected Objects	By default, the source schema name is used as the destination schema name, and the source table name is used as the destination table name. If you want to modify the schema name that receives data in the destination ApsaraDB RDS for PostgreSQL instance, in the Selected Objects pane, right-click the schema of the table to be migrated. In the Edit Schema dialog box that appears, modify Schema Name. Note You can also right-click the table to be migrated in the Selected Objects pane to modify the destination table name or column names, or set a WHERE clause to filter data. For more information, see Set filter conditions and Object name mapping. To select SQL operations for incremental migration, right-click the object to be migrated in the Selected Objects pane, and select the required SQL operations in the dialog box that appears. To remove an already selected migration object, in the Selected Objects pane, click the object to be migrated and click to move it to the Source Objects pane.

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 based on your business needs. This example does not require a tag.
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 contact. 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 an 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.

Prerequisites

Usage notes

Billing

SQL operations that support incremental migration

Permissions required for database accounts

Prerequisites

Procedure

From the DTS console

From the DMS console