This topic describes how to migrate data from a PolarDB-X V2.0 1.0 instance to a PolarDB-X V2.0 2.0 instance by using Data Transmission Service (DTS).
- The source PolarDB-X V2.0 1.0 and destination PolarDB-X V2.0 2.0 instances are created. They are compatible with MySQL 5.7. For more information, see Create a instance and Create a database.
- The available storage space of the destination instance is larger than the total size of the data in the source instance.
|Limits on the source database||
|Migration type||Task configuration fee||Internet traffic fee|
|Schema migration and full data migration||Free of charge.||Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Billing overview.|
|Incremental data migration||Charged. For more information, see Billing overview.|
- Schema migration
DTS migrates the schemas of required objects from the source database to the destination database.
- Full data migration
DTS migrates historical data of required objects from the source database to the destination database.
- Incremental data migration
After full data migration is complete, DTS migrates incremental data from the source database to the destination database. Incremental data migration allows you to ensure service continuity when you migrate data between self-managed databases.
SQL operations that can be migrated
|Operation type||SQL statement|
|DML||INSERT, UPDATE, and DELETE|
Permissions required for database accounts
|Database||Schema migration||Full data migration||Incremental data migration||References|
|PolarDB-X 1.0 instance||The SELECT permission||The SELECT permission||The SELECT permission on the objects to be migrated, the REPLICATION SLAVE permission, and the REPLICATION CLIENT permission. DTS automatically grants these permissions to the database account.||Manage accounts|
|PolarDB-X 2.0 instance||Read and write permissions|
- Go to the Data Migration page.
- Log on to the DMS console.
- In the top navigation bar, click DTS.
- In the left-side navigation pane, choose .
- From the drop-down list next to Data Migration Tasks, select the region in which your data migration instance resides. Note If you use the new DTS console, select the region in which your data migration instance resides in the upper-left corner.
- Click Create Task. On the page that appears, configure the source and destination databases.
Section Parameter Description N/A Task Name
DTS automatically generates a task name. We recommend that you specify an informative name to identify the task. You do not need to use a unique task name.
Source Database Database Type Select PolarDB-X 1.0. Access Method Select Alibaba Cloud Instance. Instance Region The region where the source PolarDB-X 1.0 instance resides. Replicate Data Across Alibaba Cloud Accounts Specify whether to migrate data across Alibaba Cloud accounts. In this example, No is selected. Instance ID The ID of the source PolarDB-X 1.0 instance. Database Account The database account of the source PolarDB-X 1.0 instance. Database Password
Enter the password of the database account.
Destination Database Database Type Select PolarDB-X 2.0. Access Method Select Alibaba Cloud Instance. Instance Region The region where the destination PolarDB-X 2.0 instance resides. Instance ID The ID of the destination PolarDB-X 2.0 instance. Database Account The database account of the destination PolarDB-X 2.0 instance. Database Password
Enter the password of the database account.
- In the lower part of the page for this step, click Test Connectivity and Proceed. Warning
- If the source or destination database is an Alibaba Cloud database instance, such as an ApsaraDB RDS for MySQL or ApsaraDB for MongoDB instance, DTS automatically adds the CIDR blocks of DTS servers to the whitelist of the instance. If the source or destination database is a self-managed database hosted on an Elastic Compute Service (ECS) instance, DTS automatically adds the CIDR blocks of DTS servers to the security group rules of the ECS instance. For more information, see Add the CIDR blocks of DTS servers to the security settings of on-premises databases. If the source or destination database is a self-managed database that is deployed in a data center or provided by a third-party cloud service provider, you must manually add the CIDR blocks of DTS servers to the whitelist of the database to allow DTS to access the database.
- If the CIDR blocks of DTS servers are automatically or manually added to the whitelist of the database, Alibaba Cloud database instance, or ECS security group rules, security risks may arise. Therefore, before you use DTS to migrate data, you must understand and acknowledge the potential risks and take preventive measures, including but not limited to the following measures: enhancing the security of your username and password, limiting the ports that are exposed, authenticating API calls, regularly checking the whitelist or ECS security group rules and forbidding unauthorized CIDR blocks, or connecting the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.
- After the DTS task is complete or released, we recommend that you manually detect and remove the added CIDR blocks from the whitelist or ECS security group rules.
- Select objects for the task and configure advanced settings.
- Basic Settings
Parameter or setting Description Task Stages
Note If Incremental Data Migration is not selected, we recommend that you do not write data to the source instance during data migration. This ensures data consistency between the source and destination instances.
- To perform only full data migration, select Schema Migration and Full Data Migration.
- To ensure service continuity during data migration, select Schema Migration, Full Data Migration, and Incremental Data Migration.
Processing Mode of Conflicting Tables
Precheck and Report Errors: checks whether the destination database contains tables that have the same names as tables in the source database. If the source and destination databases do not contain identical table names, the precheck is passed. Otherwise, an error is returned during precheck and the data migration task cannot be started.Note You can use the object name mapping feature to rename the tables that are migrated to the destination database. You can use this feature if the source and destination databases contain identical table names and the tables in the destination database cannot be deleted or renamed. For more information, see Map object names .
- Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases.
Warning If you select Ignore Errors and Proceed, data consistency is not guaranteed and your business may be exposed to potential risks.
- If the source and destination databases have the same schema, DTS does not migrate data records that have the same primary keys as data records in the destination database.
- If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails.
Capitalization of Object Names in Destination Instance
Specify the capitalization of database names, table names, and column names in the destination instance. By default, DTS default policy is selected. You can select other options to make sure that the capitalization of object names is consistent with that of the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.
Select one or more objects from the Source Objects section and click the icon to add the objects to the Selected Objects section.
Note If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be migrated.
- To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object.
- To rename multiple objects at a time, click in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time.
- Advanced Settings
Parameter Description Set AlertsSpecify whether to set alerts for the data migration task. If the task fails or the migration latency exceeds the threshold, the alert contacts will receive notifications.
- Select No if you do not want to set alerts.
- Select Yes to set alerts. In this case, you must also set the alert threshold and alert contacts.
Retry Time for Failed ConnectionThe retry time range for failed connections. Valid values: 10 to 1440. Unit: minutes. Default value: 120. We recommend that you set the retry time range to more than 30 minutes. If DTS reconnects to the source and destination databases within the specified time range, DTS resumes the data migration task. Otherwise, the data migration task fails.Note
- If you set different retry time ranges for multiple data migration tasks that have the same source or destination database, the value that is set later takes precedence.
- When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business needs. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.
Configure ETLSpecify whether you want to enable the ETL feature. For more information, see What is ETL?.
- If you select Yes, the ETL feature is enabled. You must specify a policy in the text box.
- If you select No, the ETL feature is disabled.
- Basic Settings
- Click Next: Save Task Settings and Precheck in the lower part of the page. Note
- Before you can start the data migration task, DTS performs a precheck. You can start the data migration task only after the task passes the precheck.
- If the task fails to pass the precheck, you can click the icon next to each failed item to view details.
- You can troubleshoot the issues based on the causes and run a precheck again.
- If you do not need to troubleshoot the issues, you can ignore failed items and run a precheck again.
- Wait until the Success Rate becomes 100%. Then, click Next: Purchase Instance.
- On the Purchase Instance page, specify the Instance Class parameter for the data migration instance. The following
table describes the parameter.
Section Parameter Description Parameters Instance Class
DTS provides several instance classes that have different performance in migration speed. You can select an instance class based on your business scenario. For more information, see Specifications of data migration instances.
- Read and select Data Transmission Service (Pay-as-you-go) Service Terms.
- Click Buy and Start to start the data migration task. You can view the progress of the task in the task list.