This topic describes how to migrate data from a self-managed HBase database to an AnalyticDB for MySQL V3.0 cluster by using Data Transmission Service (DTS).

Prerequisites

  • The database versions of the self-managed HBase database and the AnalyticDB for MySQL V3.0 cluster are supported by DTS. For more information , see Overview of data migration scenarios.
  • The destination AnalyticDB for MySQL V3.0 cluster is created. For more information, see Create a cluster.
  • The available storage space of the destination AnalyticDB for MySQL V3.0 cluster is larger than the total size of the data in the self-managed HBase database.

Limits

Note
  • During schema migration, DTS migrates foreign keys from the source database to the destination database.
  • During full data migration and incremental data migration, DTS temporarily disables the constraint check and cascade operations on foreign keys at the session level. If you perform the cascade and delete operations on the source database during data migration, data inconsistency may occur.
CategoryDescription
Limits on the source database
  • Bandwidth requirements: The server to which the source database belongs must have sufficient egress bandwidth. Otherwise, the data migration speed is affected.
  • The tables to be migrated must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.
  • If you select tables as the objects to be migrated and you need to edit tables (such as renaming tables or columns), up to 1,000 tables can be migrated in a single data migration task. If you run a task to migrate more than 1,000 tables, a request error occurs. In this case, we recommend that you split the tables to be migrated, configure multiple tasks to migrate the tables, or configure a task to migrate the entire database.
  • Limits on operations:
    • During schema migration and full data migration, do not perform data definition language (DDL) operations to change the schemas of databases or tables. Otherwise, the data migration task fails.
    • In this scenario, DTS does not support incremental data migration. To ensure data consistency, we recommend that you do not write data to the source instance during data migration.
Other limits
  • In this scenario, DTS supports only schema migration and full data migration. DTS does not support incremental data migration.
  • The characters in the source objects can only be alphanumeric (a to z, A to Z, and 0 to 9). If an object contains other types of characters, schema migration fails.
  • AnalyticDB for MySQL has limits on the usage of disk space. If the disk space usage of the nodes in an AnalyticDB for MySQL cluster reaches 80%, the performance of data writing to the destination database is compromised and the DTS task is delayed. If the usage reaches 90%, data cannot be written to the destination database and error messages are returned. We recommend that you estimate the required disk space based on the objects that you want to migrate. You must make sure that the destination cluster has sufficient storage space.
  • Before you migrate data, evaluate the impact of data migration on the performance of the source and destination databases. We recommend that you migrate data during off-peak hours. During full data migration, DTS uses read and write resources of the source and destination databases. This may increase the loads of the database servers.
  • During full data migration, concurrent INSERT operations cause fragmentation in the tables of the destination database. After full data migration is completed, the tablespace of the destination database is larger than that of the source database.
  • DTS attempts to resume data migration tasks that failed within the last seven days. Before you switch workloads to the destination cluster, stop or release the data migration task. You can also run the revoke command to revoke the write permissions from the accounts that are used by DTS to access the destination cluster. Otherwise, the data in the source database will overwrite the data in the destination cluster after the task is resumed.

Billing

Migration typeInstance configuration feeInternet traffic fee
Schema migration and full data migrationFree of charge. Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Billing overview.

Migration types

  • Schema migration

    Data Transmission Service (DTS) migrates the schemas of objects from the source database to the destination database.

    DTS supports schema migration for tables.
    Note DTS can migrate the tables of an entire database or a single table.
  • Full data migration

    DTS migrates the existing data of objects from the source database to the destination database.

Permissions required for database accounts

DatabaseSchema migrationFull data migration
Self-managed HBase databaseN/A
AnalyticDB for MySQL V3.0 clusterRead and write permissions on the destination database
For more information about how to create a database account for an AnalyticDB for MySQL V3.0 cluster and grant permissions to the database account, see Create a database account.

Procedure

  1. Go to the Data Migration Tasks page.
    1. Log on to the Data Management (DMS) console.
    2. In the top navigation bar, click DTS.
    3. In the left-side navigation pane, choose DTS (DTS) > Data Migration.
    Note
  2. From the drop-down list next to Data Migration Tasks, select the region in which the 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 page that appears, configure the source and destination databases.
    Warning After you select the source and destination instances, we recommend that you read the limits displayed at the top of the page. This helps ensure that the task properly runs or prevent data inconsistency.
    SectionParameterDescription
    N/ATask Name

    The name of the task. DTS automatically generates a task name. We recommend that you specify an informative name to identify the task. You do not need to specify a unique task name.

    Source DatabaseSelect an existing DMS database instance
    The database instance that you want to use. You can choose whether to use an existing instance based on your business requirements.
    • If you use an existing instance, DTS automatically applies the parameter settings of the source database.
    • If you do not use an existing instance, you must configure the parameters for the database.
    Database TypeThe type of the source database. Select HBase.
    Access Method The access method of the source database. Select Public IP Address.
    Note If your source database is a self-managed database, you must deploy the network environment for the database. For more information, see Preparation overview.
    Instance RegionThe region in which the self-managed HBase database resides.
    ZooKeeper URLThe endpoints of the ZooKeeper servers that are configured for the self-managed HBase database. Enter each endpoint in the <IP address> or <Domain name:Port number> format. Separate multiple endpoints with commas (,).
    Destination DatabaseSelect an existing DMS database instance
    The database instance that you want to use. You can choose whether to use an existing instance based on your business requirements.
    • If you use an existing instance, DTS automatically applies the parameter settings of the instance.
    • If you do not use an existing instance, you must configure the parameters for the database.
    Database TypeThe type of the destination database. Select AnalyticDB for MySQL 3.0.
    Access MethodThe access method of the destination database. Select Alibaba Cloud Instance.
    Instance RegionThe region in which the destination AnalyticDB for MySQL V3.0 cluster resides.
    Instance IDThe ID of the destination AnalyticDB for MySQL V3.0 cluster.
    Database AccountThe database account of the destination AnalyticDB for MySQL V3.0 cluster. For more 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 of the database account.

  4. If a whitelist is configured for your self-managed database, you must add the CIDR blocks of DTS servers to the whitelist. Then, click Test Connectivity and Proceed.
    Warning If the CIDR blocks of DTS servers are automatically or manually added to the whitelist of a database or an 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: 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.
  5. Configure objects to migrate and advanced settings.
    • Basic Settings
      Parameter or settingDescription
      Migration TypeBy default, Schema Migration and Full Data Migration are selected.
      Note
      • In this scenario, DTS does not support incremental data migration. To ensure data consistency, we recommend that you do not write data to the source database during data migration.
      • The schema of and data in the table that is created by executing the CREATE TABLE statement can be migrated to the destination database.
      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 the 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 tables that have identical 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 inconsistency may occur, 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 some columns are migrated or the data migration task fails. Proceed with caution.
      Merge Tables
      • Yes: If you select this option, DTS adds the __dts_data_source column to each table to record data sources. For more information, see Enable the multi-table merging feature.
      • No: This option is selected by default.
      Note If you set this parameter to Yes, all of the selected source tables in the task are merged into the destination table. If you do not need to merge specific source tables, you can create a separate data migration task for these tables.
      Warning We recommend that you do not perform DDL operations to change the schemas of source databases or tables. Otherwise, data inconsistency may occur or the data migration task fails.
      Source Objects

      Select one or more objects from the Source Objects section and click the Rightwards arrow icon to add the objects to the Selected Objects section.

      Note
      • You can select tables or databases as the objects to be migrated. If you select tables as the objects to be migrated, DTS does not migrate other objects such as views, triggers, and stored procedures to the destination database.
      • If you select a database as the object to be migrated, DTS migrates data based on the following default rules:
        • If the table to be migrated in the source database has a primary key, such as a single-column primary key or a composite primary key, the primary key columns are specified as the distribution keys.
        • If the table to be migrated in the source database does not have a primary key, an auto-increment primary key column is automatically generated in the destination table. This may cause data inconsistency between the source and destination databases.
      Selected Objects
      • 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 Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time.
      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 specify WHERE conditions to filter data, right-click an object in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see Use SQL conditions to filter data.
    • Advanced Settings
      ParameterDescription
      Set Alerts
      Specifies 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. Valid values:
      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 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 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 share the same source or destination database, the value that is set later takes precedence.
      • If DTS retries a connection, you are charged for the operation of the DTS instance. We recommend that you specify the retry time based on your business needs and release the DTS instance at your earliest opportunity after the source and destination instances are released.
      Capitalization of Object Names in Destination Instance

      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 ensure that the capitalization of object names is consistent with the default capitalization of object names in the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.

      Configure ETL
      Specifies whether to configure the extract, transform, and load (ETL) feature. For more information, see What is ETL?. Valid values:
  6. Specify the primary key columns and distribution keys of the tables that you want to migrate to the AnalyticDB for MySQL V3.0 cluster.
    Note
    • If you select Schema Migration as the migration type, you must specify the type, primary key column, and distribution key for the tables that you want to migrate to the AnalyticDB for MySQL V3.0 cluster. For more information, see CREATE TABLE.
    • In the Primary Key Column field, you can specify multiple columns to form a composite primary key. In this case, you must specify one or more primary key columns as the distribution keys.
  7. In the lower part of the page, click Next: Save Task Settings and Precheck.
    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 troubleshoot the issues based on the causes, 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 an 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 the Success Rate value becomes 100%. Then, click Next: Purchase Instance.
  9. On the Purchase Instance page, specify the Instance Class parameter for the data migration instance. The following table describes the parameter.
    SectionParameterDescription
    ParametersInstance Class

    DTS provides several instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Specifications of data migration instances.

  10. Read and select the check box to agree to Data Transmission Service (Pay-as-you-go) Service Terms.
  11. Click Buy and Start to start the data migration task. You can view the progress of the task in the task list.