This topic describes how to migrate data from an ApsaraDB for Redis instance to another ApsaraDB for Redis instance by using Data Transmission Service (DTS). You can also follow the procedure to configure data migration tasks for self-managed Redis databases. DTS supports full data migration and incremental data migration. When you configure a data migration task, you can select both of the supported migration types to ensure service continuity.

Prerequisites

  • The source and destination ApsaraDB for Redis instances are created. For more information, see Create an ApsaraDB for Redis instance.
  • For self-managed Redis databases, the database versions must be 2.8, 3.0, 3.2, 4.0, 5.0, or 6.0.
  • The engine versions of the ApsaraDB for Redis instances are 4.0 (Community Edition) or 5.0 (Community Edition or Enhanced Edition).
  • The available storage space of the destination ApsaraDB for Redis instance is larger than the total size of the data in the source ApsaraDB for Redis instance.
  • The disk types of the source and destination ApsaraDB for Redis instances are local disk rather than cloud disk.

Supported source and destination databases

You can use DTS to migrate data between the following types of Redis databases.

Source database Destination database
  • ApsaraDB for Redis instance
  • Self-managed database that is hosted on Elastic Compute Service (ECS)
  • Self-managed database that is connected over Express Connect, VPN Gateway, or Smart Access Gateway
  • Self-managed database that is connected over Cloud Enterprise Network (CEN)
  • ApsaraDB for Redis instance
  • Self-managed database that is hosted on ECS
  • Self-managed database that is connected over Express Connect, VPN Gateway, or Smart Access Gateway
  • Self-managed database that is connected over CEN

Limits

Migration types

Migration type Description
Full data migration

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

Incremental data migration

After full data migration is completed, 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.

Commands that can be migrated

  • APPEND
  • BITOP, BLPOP, BRPOP, and BRPOPLPUSH
  • DECR, DECRBY, and DEL
  • EVAL, EVALSHA, EXEC, EXPIRE, and EXPIREAT
  • FLUSHALL and FLUSHDB
  • GEOADD and GETSET
  • HDEL, HINCRBY, HINCRBYFLOAT, HMSET, HSET, and HSETNX
  • INCR, INCRBY, and INCRBYFLOAT
  • LINSERT, LPOP, LPUSH, LPUSHX, LREM, LSET, and LTRIM
  • MOVE, MSET, MSETNX, and MULTI
  • PERSIST, PEXPIRE, PEXPIREAT, PFADD, PFMERGE, PSETEX, and PUBLISH
  • RENAME, RENAMENX, RESTORE, RPOP, RPOPLPUSH, RPUSH, and RPUSHX
  • SADD, SDIFFSTORE, SELECT, SET, SETBIT, SETEX, SETNX, SETRANGE, SINTERSTORE, SMOVE, SPOP, SREM, and SUNIONSTORE
  • ZADD, ZINCRBY, ZINTERSTORE, ZREM, ZREMRANGEBYLEX, ZUNIONSTORE, ZREMRANGEBYRANK, and ZREMRANGEBYSCORE

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 Redis.
    Access Method Select Alibaba Cloud Instance. In this example, the source and destination databases are both ApsaraDB for Redis instances. You can also follow the procedure to configure data migration tasks for other types of Redis databases.
    Instance Region Select the region where the source ApsaraDB for Redis instance resides.
    Replicate Data Across Alibaba Cloud Accounts Select No.
    Instance ID Select the ID of the source ApsaraDB for Redis instance.
    Database Password Enter the database password of the source ApsaraDB for Redis instance. The database account that corresponds to the password must have the read permissions. If you forget the password, you can reset the password. For more information, see Change or reset the password.
    • If you use the default account, whose username is the same as the instance ID, you can enter only the password.
    • If you create a custom account, you must specify the password in the <Custom account>:<Password> format. Example: testaccount:Test1234.
    Note This parameter is optional and can be left blank if no database password is set.
    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.
    Destination 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 Redis.
    Access Method Select Alibaba Cloud Instance.
    Instance Region Select the region where the destination ApsaraDB for Redis instance resides.
    Instance ID Select the ID of the destination ApsaraDB for Redis instance.
    Database Password Enter the database password of the destination ApsaraDB for Redis instance. The database account that corresponds to the password must have the read permissions. If you forget the password, you can reset the password. For more information, see Change or reset the password.
    • If you use the default account, whose username is the same as the instance ID, you can enter only the password.
    • If you create a custom account, you must specify the password in the <Custom account>:<Password> format. Example: testaccount:Test1234.
    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. In the lower part of the page, click Test Connectivity and Proceed.
  5. Select objects for the task and configure advanced settings.
    • Basic SettingsBasic Settings
      Parameter Description
      Task Stages
      • 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 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.

      For more information, see Migration types.

      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.

      • 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.
      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 only databases as the objects to be migrated. You cannot select keys as the objects to be migrated.
      Rename Databases and Tables In this scenario, you cannot rename objects.
      Select the commands to be migrated In the Selected Objects section, right-click an object. In the dialog box that appears, select the commands that you want to migrate. For more information, see Commands that can be migrated.
    • 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.
  6. 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.
  7. Wait until the Success Rate becomes 100%. Then, click Next: Purchase Instance.
  8. 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.

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