This topic describes how to synchronize 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

Category Description
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 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 Pricing.

Migration types

  • Schema migration

    DTS migrates the schemas of the required 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 historical data of the required objects from the source database to the destination database.

Permissions required for database accounts

Database Schema migration Full data migration
Self-managed HBase database N/A
AnalyticDB for MySQL V3.0 The read and write permissions on the destination database
For more information about how to create and authorize a database account for an AnalyticDB for MySQL V3.0 cluster, see Create a database account.

Procedure

  1. Go to the Data Migration page of the new DTS console.
    Note You can also log on to the Data Management (DMS) console. In the top navigation bar, choose DTS > Data Migration.
  2. In the upper-left corner of the page, select the region where the data migration instance resides.
    Select a region
  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 you create and run the data migration task.
    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 Select Template
    If the connection settings of the instance has been saved as a template, you can select the connection name. DTS automatically applies the saved connection settings.
    Note
    • You can modify the connection settings of a template.
    • To edit the template name, you can click Edit Template Name at the bottom of the Source Database section.
    • The modified connection template will take effect the next time you select the connection template. The database instance that you have configured by using the template is not affected.
    Database Type Select HBase.
    Access Method Select Self-managed Database with 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 Region Select the region where the self-managed HBase database resides.
    ZooKeeper URL Enter the 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 Database Save as Template
    Click Save as Template. In the dialog box that appears, set the name of the database connection, and click OK. The connection settings of the database instance is saved as a template.
    Note We recommend that you specify an informative name to identify the database connection. You do not need to use a unique name.
    Select Template
    If the connection settings of the instance has been saved as a template, you can select the connection name. DTS automatically applies the saved connection settings.
    Note
    • You can modify the connection settings of a template.
    • To edit the template name, you can click Edit Template Name at the bottom of the Source Database section.
    • The modified connection template will take effect the next time you select the connection template. The database instance that you have configured by using the template is not affected.
    Destination Database Database Type Select AnalyticDB for MySQL 3.0.
    Access Method Select Alibaba Cloud Instance.
    Instance Region Select the region where the destination AnalyticDB for MySQL V3.0 cluster resides.
    Instance ID Select the ID of the destination AnalyticDB for MySQL V3.0 cluster.
    Database Account Enter the database account of the destination AnalyticDB for MySQL V3.0 cluster. For information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password

    Enter the password of the database account.

    Save as Template
    Click Save as Template. In the dialog box that appears, set the name of the database connection, and click OK. The connection settings of the database instance is saved as a template.
    Note We recommend that you specify an informative name to identify the database connection. You do not need to use a unique name.
  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.
  5. Select objects for the task and configure advanced settings.
    • Basic SettingsBasic Settings
      Parameter Description
      Task Stages Schema Migration and Full Data Migration are selected by default.
      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 instance during 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 some columns are migrated or the data migration task fails.
      Merge Tables
      • If you select Yes, DTS adds the __dts_data_source column to each table to record data sources.
      • No 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. To merge only the data source columns of specific tables, you can create two data migration tasks.
      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 migration task fails.
      Select Objects

      Select one or more objects from the Source Objects section and click the Rightwards arrow icon to move 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.
      Rename Databases and Tables
      • 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.
      Filter data

      You can specify WHERE conditions to filter data. For more information, see Use SQL conditions to filter data.

    • Advanced SettingsAdvanced Settings
      Parameter Description
      Set Alerts
      Specify 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 Connections
      Specify the retry time for failed connections. Valid values: 10 to 1440. Unit: minutes. Default value: 120. We recommend that you set the retry time to more than 30 minutes. If DTS reconnects to the source and destination databases within the specified time, DTS resumes the data migration task. Otherwise, the data migration task fails.
      Note
      • If multiple DTS instances have the same source or destination database, the lowest value takes effect. For example, the retry time is set to 30 minutes for Instance A and 60 minutes for Instance B, DTS retries failed connections at an interval of 30 minutes.
      • When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time based on your business needs. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.
      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.

  6. Specify the primary key columns and distribution keys of the tables that you want to migrate to the AnalyticDB for MySQL cluster.
    Set partitioned tables
    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 select 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, you can click the Info icon 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.
  8. Wait until the Success Rate 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.
    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.

  10. Read and select 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.