You can use DTS to migrate data between various types of data sources. Typical scenarios include data migration to Alibaba Cloud, data migration between instances within Alibaba Cloud, and database splitting and scale-out. DTS supports data migration between homogeneous and heterogeneous data sources. It also supports ETL features such as data mapping at three levels (databases, tables, and columns) and data filtering.

For more information about data migration in various scenarios, see Overview.

Databases and migration types

For more information, see Database and migration types.

Online data migration

The DTS server connects to the source and destination instances to ensure service continuity. After you configure the source instance, destination instance, and objects to be migrated, DTS automatically completes the entire data migration process.

Migration types

DTS supports schema migration, full data migration, and incremental data migration. You can select all of these types to migrate data with minimized downtime.

Migration type Description
Schema migration

DTS migrates the schemas of the objects that you have selected from the source instance to the destination instance. Tables, views, triggers, and stored procedures can be migrated.

For schema migration between heterogeneous databases, DTS converts the schema syntax based on the syntax of the source and destination databases. For example, it converts the NUMBER data type in Oracle databases to the DECIMAL data type in MySQL databases.

Full data migration DTS migrates historical inventory data of the objects that you have selected from the source database to the destination database. If you select only schema migration and full data migration, new data generated in the source database will not be migrated to the destination database.
Note To ensure data consistency, we recommend that you do not write new data into the source database during full data migration. To migrate data with minimized downtime, you must select schema migration, full data migration, and incremental data migration.
Incremental data migration DTS retrieves static snapshots from the source database and migrates the snapshot data to the destination database. Then, DTS synchronizes the incremental data generated in the source database to the destination database in real time.
Note During incremental data migration, data between the source and destination databases are synchronized in real time. The migration task does not automatically end. You need to manually end the migration task.

ETL features

Data migration supports the following ETL features:
  • Object name mappings at database, table, and column levels: you can migrate data between two databases, tables, or columns that have different names.
  • Data filtering: you can use SQL conditions to filter the required data in a specific table. For example, you can specify a time range to migrate only the latest data.

Alerts

Data migration supports sending alerts in case of exceptions. When an exception occurs, DTS immediately sends an SMS alert to the task creator, allowing the creator to promptly handle the exception.

Migration tasks

A migration task is a basic unit of data migration. To migrate data, you must create a migration task in the DTS console. To create a migration task, you must configure the required information such as the type of connections to the source and destination instances, the migration type, and the objects to be migrated. You can create, manage, stop, and delete data migration tasks in the DTS console.

The following table describes the statuses of a migration task during creation and running.

Task status Description Available operations
Not Started The configuration of the migration task is complete, but the precheck is not performed. Perform the precheck and delete the migration task.
Prechecking A precheck is being performed before the migration task is started. Delete the migration task.
Precheck Passed The migration task has passed the precheck but is not started. Start and delete the migration task.
Migrating Data is being migrated. Pause, stop, and delete the migration task.
Migration Failed The migration task has encountered an exception, and you can determine the specific phase in which the migration failed based on the task progress. Delete the migration task.
Paused The migration task is paused. Start and delete the migration task.
Completed The migration task is complete, or you have clicked End to stop data migration. Delete the migration task.

If a migration task is in the Migration Failed state, the task will be started and resumed within seven days. To stop data migration, you must manually release or stop the migration task.

References