This topic describes how to use Data Transmission Service (DTS) to perform full and incremental data migration between Redis and the Orca feature of PolarDB for MySQL. This topic also describes how to migrate data from an Orca database to other databases.
Preparations
The Orca feature is enabled for the PolarDB for MySQL cluster.
An Orca account has been created for DTS logon.
Limits
When an Orca database is used as the source, incremental data migration is not supported.
Only the VPN Gateway connection type is supported for an Orca database, regardless of whether it is used as a source or a destination.
Two-way synchronization using Data Transmission Service (DTS) is not supported.
Redis version limits:
When an Orca database is the source, the destination Redis version must be compatible with the Redis versions supported by Orca.
If you use other Redis products as the source, their version must not be later than the Redis version that is supported by Orca (Redis 7.0) or earlier than version 2.8.0.
The Orca feature supports only the DB0 database of Redis. If the source Redis instance uses other databases, such as DB1 to DB255, the data in these databases cannot be migrated to an Orca database.
Billing
Migration type | Link configuration fee | Data transfer cost |
Full migration | Free of charge. | Data migration over the Internet is charged. For more information, see Billing items. |
Incremental migration | Charged. For more information, see Billing items. |
Example
This example shows how to migrate data from a Tair (Redis-compatible) instance to an Orca database.
Step 1: Configure the source and destination databases
Log on to the page and click Create Task to go to the task configuration page.
Configure the source and destination databases.
Category
Configuration
Description
Example image
N/A
Task Name
DTS automatically generates a task name. Specify a descriptive name for easy identification. The name does not need to be unique.
Source Database
Database Type
Select the database type based on the deployment location of the source database. This example uses .
NoteIf the source or destination database is hosted on a third-party cloud platform, you must perform additional preparations.
Connection Type
Select Cloud Instance.
NoteConfigure this parameter as needed.
Instance Region
Select the region where the Tair (Redis-compatible) instance resides.
NoteIf the source or destination database is hosted on a third-party cloud platform, you can select a nearby region.
Cross-account
Configure this parameter as needed. This example uses No (the instances are in the same account).
NoteSupport is available for configuring data migration or synchronization for instances in different Alibaba Cloud accounts.
Instance ID
Select the Tair (Redis-compatible) instance that belongs to your account.
Authentication Method
Select Password Logon.
Database Password
Enter the password of the Tair (Redis-compatible) instance.
Connection Method
Based on the configuration of the Tair (Redis-compatible) instance, select Non-encrypted or SSL-encrypted.
Destination Database
Database Type
Set this to .
Connection Type
Select Leased Line/VPN Gateway/Smart Access Gateway.
Instance Region
Select the region where the PolarDB cluster resides.
VPC Connected to Destination Database
Select the VPC of the PolarDB cluster.
Instance Mode
Set this to Basic Edition. Cluster Edition is not supported.
Domain Name or IP Address
Enter the Orca private endpoint.
Port
Enter the port for the Orca private endpoint. Default value: 6379.
Authentication Method
Select Account And Password Logon.
Database Password
Connection Method
Based on the configuration of the PolarDB cluster, select Non-encrypted or SSL-encrypted.
Primary/Standby vSwitch for VPC Data Channel
Select the vSwitches for the VPC data channel that DTS uses to access your data source.
Click Test Connection And Proceed. In the Authorize DTS Servers To Access dialog box, add the IP addresses of the Destination to the whitelist of the PolarDB cluster, and then click Test Connection. If the connection is successful, the system automatically proceeds to the next step to configure the task object.
WarningIf the CIDR blocks of DTS servers are automatically or manually added to the whitelist of the database or instance, or to the 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: enhance the security of your username and password, limit the ports that are exposed, authenticate API calls, regularly check the whitelist or ECS security group rules and forbid unauthorized CIDR blocks, or connect the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.
Step 2: Configure the task object
Configure the migration object.
Configuration
Description
Example image
Migration Types
To perform only full migration, select Full Migration.
To perform only incremental migration, select Incremental Migration.
To perform migration with minimal downtime, select both Full Migration and Incremental Migration.
NoteIf you do not select Incremental Data Migration, do not write new data to the source Tair (Redis-compatible) instance during data migration to ensure data consistency.
Processing Mode for Existing Destination Tables
Precheck and Report Errors: checks whether the destination database is empty. If the destination database is empty, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started.
Ignore Errors and Proceed: skips the Check the existence of objects in the destination database. check item.
WarningIf you select Ignore Errors and Proceed, the data in the source database overwrites the data in the destination database that has the same keys as the source data. This may cause data loss in the destination database. Proceed with caution.
Migration Objects
Select one or more objects from the Source Objects section. Click the
icon to add the objects to the Selected Objects section. NoteMigration objects are selected at the database level.
Select 0 for Source Objects. Orca currently supports only DB0.
Click Next: Advanced Settings and configure the advanced settings.
Click Next: Data Verification and then configure the settings as needed.
Step 3: Precheck
After you complete the preceding configurations, if you want to use the data verification feature, see Configure data verification. Then, click Next: Save Task And Precheck in the lower-right corner of the page and wait for the precheck to complete.
DTS performs a precheck before the migration task starts. You can start the migration task only after it passes the precheck.
If the precheck fails, click
next to the failed check item to view the details.Fix the issue based on the prompt and run the precheck again.
If you do not need to resolve an alert item, you can click Confirm To Shield or Ignore And Precheck Again to skip the item and rerun the precheck.
Step 4: Purchase the instance
In the Confirm Settings dialog box, configure the Channel Specification parameter. Then, read and select Data Transmission Service (Pay-as-you-go) Service Terms.
Click Purchase And Start to begin the migration task.
For a full data migration task:
Do not manually stop the task. Otherwise, the migrated data may be incomplete. Wait for the task to automatically stop.
For an incremental data migration task:
The migration task does not automatically stop. You must manually stop it.
NoteYou must manually stop the task at an appropriate time, such as during off-peak hours or before you switch your workloads to the destination instance.
When the task status is Incremental Migration and the latency is No Latency, stop writing data to the source database for a few minutes. At this point, the Incremental Migration status may show a latency.
Wait until the Incremental Migration status changes to No Latency, and then manually stop the task.
Wait for the migration to complete.