Migrate data from an ApsaraDB RDS for MySQL instance to a Tair (Redis OSS-Compatible) instance

Prerequisites

• The tables to be migrated from the source database must contain primary keys.

• A destination Tair (Redis OSS-Compatible) instance is created, whose available storage space is larger than the total size of the data in the source ApsaraDB RDS for MySQL instance. For more information, see Step 1: Create an instance.

  Note

  For information about the supported versions of the source and destination databases, see Overview of data migration scenarios.

Limits

Billing

SQL operations that can be incrementally migrated

Permissions required for database accounts

Procedure

1. Go to the Data Migration Tasks page.

   1. Log on to the Data Management (DMS) console.

   2. In the top navigation bar, move the pointer over DTS.

   3. Choose DTS (DTS) > Data Migration.

   Note

   • The actual operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode and Customize the layout and style of the DMS console.

   • You can also go to the Data Migration page of the new DTS console.

2. From the drop-down list on the right side of Data Migration Tasks, select the region in which your data migration instance resides.

   Note

   If you use the new DTS console, you must select the region in which the data migration instance resides in the upper-left corner.

3. Click Create Task. On the Create Task wizard, configure the source and destination databases. The following table describes the parameters.

   Section	Parameter	Description

   Section	Parameter	Description
   N/A	Task Name	The name of the DTS task. DTS automatically generates a task name. We recommend that you specify a descriptive name that makes it easy to identify the task. You do not need to specify a unique task name.
   Source Database	Select an existing DMS database instance. (Optional. If you have not registered a DMS database instance, ignore this option and configure database settings in the section below.)	The database that you want to use. You can choose whether to use an existing database based on your business requirements. If you select an existing database, DTS automatically populates the parameters for the database. If you do not select an existing database, you must configure the following database information.
   	Database Type	The type of the source database. Select MySQL.
   	Access Method	The access method of the source database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the source ApsaraDB RDS for MySQL instance resides.
   	Replicate Data Across Alibaba Cloud Accounts	Specifies whether to migrate data across Alibaba Cloud accounts. In this example, No is selected.
   	RDS Instance ID	The ID of the source ApsaraDB RDS for MySQL instance.
   	Database Account	The database account of the source ApsaraDB RDS for MySQL instance. For information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password that is used to access the database.
   	Encryption	Specifies whether to encrypt the connection to the database. You can select Non-encrypted or SSL-encrypted based on your business requirements. If you want to set this parameter to SSL-encrypted, you must enable SSL encryption for the ApsaraDB RDS for MySQL instance before you configure the DTS task. For more information, see Use a cloud certificate to enable SSL encryption.
   Destination Database	Select an existing DMS database instance. (Optional. If you have not registered a DMS database instance, ignore this option and configure database settings in the section below.)	The database that you want to use. You can choose whether to use an existing database based on your business requirements. If you select an existing database, DTS automatically populates the parameters for the database. If you do not select an existing database, you must configure the following database information.
   	Database Type	The type of the destination database. Select Tair/Redis.
   	Access Method	The access method of the destination database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the destination Tair (Redis OSS-Compatible) instance resides.
   	Instance ID	The ID of the destination Tair (Redis OSS-Compatible) instance.
   	Database Password	The database password of the destination Tair (Redis OSS-Compatible) instance. Note The database password is in the <user>:<password> format. For example, if the username of the account that you use to log on to the destination Tair (Redis OSS-Compatible) instance is admin and the password is Rp829dlwa, the database password is admin:Rp829dlwa.

4. In the lower part of the page, click Test Connectivity and Proceed.

   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 IP address 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, and you must make sure that the ECS instance can access the database. If the self-managed database is hosted on multiple ECS instances, you must manually add the CIDR blocks of DTS servers to the security group rules of each ECS instance. 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 IP address whitelist of the database to allow DTS to access the database. For more information, see the CIDR blocks of DTS servers section of the Add the CIDR blocks of DTS servers topic.

   Warning

   If the public CIDR blocks of DTS servers are automatically or manually added to the whitelist of a database instance or to the security group rules of an ECS instance, 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 security group rules and forbidding unauthorized CIDR blocks, or connecting the database instance to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

5. Configure the objects to be migrated and advanced settings.

   Parameter	Description

   Parameter	Description
   Migration Types	To perform only full data migration, select only Full Data Migration. To ensure service continuity during data migration, select Full Data Migration and Incremental Data Migration. Note If you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
   Processing Mode of Conflicting 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. Warning If 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.
   Source Objects	Select one or more objects from the Source Objects section. Click the icon to add the objects to the Selected Objects section. Note You can select columns, tables, or databases as the objects to be migrated.
   Selected Objects	If you want to specify the destination database on the Tair (Redis OSS-Compatible) instance, right-click the schema to be migrated in the Selected Objects section, configure the following parameters, and then click OK. Mapping Name of Redis/Tair Database (0 to 255): the name of the database that is used to receive data. You need to only enter a number. Cache Mapping Mode: the format of the data that is migrated to the Tair (Redis OSS-Compatible) instance. Move the pointer over the icon next to an option to view the note. If you set the Cache Mapping Mode parameter to Key-Value Model Based on Database, Table, and Primary Key, you must also configure the Value Separation Method parameter. Note Schema names and table names are not supported by the object name mapping feature. To select the SQL operations performed on a specific database or table, right-click an object in the Selected Objects section. In the dialog box that appears, select the SQL operations that you want to migrate. For more information, see the SQL operations that can be incrementally migrated section of this topic. To specify WHERE conditions to filter data, right-click a table in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see Specify filter conditions.

6. Click Next: Advanced Settings to configure advanced settings.

   Parameter	Description

   Parameter	Description
   Dedicated Cluster for Task Scheduling	By default, DTS schedules the data migration task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data migration tasks, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.
   Set Alerts	Specifies whether to configure alerting for the data migration task. If the task fails or the migration latency exceeds the specified threshold, the alert contacts receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see the Configure monitoring and alerting when you create a DTS task section of the Configure monitoring and alerting topic.
   Retry Time for Failed Connections	The retry time range for failed connections. If the source or destination database fails to be connected after the data migration task is started, DTS immediately retries a connection within the retry time range. Valid values: 10 to 1440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS is reconnected to the source and destination databases within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you specify different retry time ranges for multiple data migration tasks that share the same source or destination database, the value that is specified 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 requirements. You can also release the DTS instance at the earliest opportunity after the source database and destination instance are released.
   Retry Time for Other Issues	The retry time range for other issues. For example, if DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set the parameter to a value greater than 10. If the failed operations are successfully performed within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Important The value of the Retry Time for Other Issues parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
   Enable Throttling for Full Data Migration	Specifies whether to enable throttling for full data migration. During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads of the database servers. You can enable throttling for full data migration based on your business requirements. To configure throttling, you must configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Full Data Migration for the Migration Types parameter.
   Enable Throttling for Incremental Data Migration	Specifies whether to enable throttling for incremental data migration. To configure throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.
   Environment Tag	The environment tag that is used to identify the DTS instance. You can select an environment tag based on your business requirements. In this example, no environment tag is selected.
   Cache Expiration Time	The validity period of the keys after data is migrated to the Tair (Redis OSS-Compatible) instance. Configure this parameter based on your business requirements. Important A value of -1 specifies that the keys never expire. This may cause the Tair (Redis OSS-Compatible) instance to run out of memory, and exceptions occur in the migration task.
   Configure ETL	Specifies whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: configures the ETL feature. You can enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: does not configure the ETL feature.

7. Save the task settings and run a precheck.

   • To view the parameters to be specified when you call the relevant API operation to configure the DTS task, move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters.

   • If you do not need to view or have viewed the parameters, 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, click View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, run a precheck again.

   • If an alert is triggered for an item during the precheck:

     • If an alert item cannot be ignored, click View Details next to the failed item and troubleshoot the issues. Then, run a precheck again.

     • If the alert item can be ignored, click Confirm Alert Details. In the View Details dialog box, click Ignore. In the message that appears, click OK. Then, click Precheck Again to run a precheck again. If you ignore the alert item, data inconsistency may occur, and your business may be exposed to potential risks.

8. Wait until Success Rate becomes 100%. Then, click Next: Purchase Instance.

9. On the Purchase Instance page, configure the Instance Class parameter for the data migration instance. The following table describes the parameters.

   Section	Parameter	Description

   Section	Parameter	Description
   New Instance Class	Resource Group	The resource group to which the data migration instance belongs. Default value: default resource group. For more information, see What is Resource Management?
   	Instance Class	DTS provides instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Instance classes of data migration instances.

10. Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.

11. Click Buy and Start. In the message that appears, click OK.

    You can view the progress of the task on the Data Migration page.