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    Tair (Redis® OSS-Compatible):Configure one-way data synchronization between Tair (Redis OSS-Compatible) instances across Alibaba Cloud accounts

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    Tair (Redis® OSS-Compatible):Configure one-way data synchronization between Tair (Redis OSS-Compatible) instances across Alibaba Cloud accounts

    Last Updated:Dec 10, 2025

    You can use Data Transmission Service (DTS) to perform one-way data synchronization between Tair (Redis OSS-Compatible) instances that belong to different Alibaba Cloud accounts. This feature is suitable for scenarios such as resource migration or merging across Alibaba Cloud accounts and business architecture adjustment.

    Prerequisites

    The destination Tair (Redis OSS-Compatible) instance is created. The available storage space of this instance is larger than the total size of data in the source instance.

    Note

    For more information about the supported instance versions, see Overview of data synchronization solutions.

    Background

    In this example, two Tair (Redis OSS-Compatible) instances are created by different Alibaba Cloud accounts. You want to synchronize data from the Tair (Redis OSS-Compatible) instance of Account A to the Tair (Redis OSS-Compatible) instance of Account B.

    You must perform the steps described in the following table to configure a data synchronization task.

    Step

    Description

    1. Use Account A that owns the source instance to log on to the Resource Access Management (RAM) console and grant the required permissions to a RAM role. For more information, see the Preparations section of this topic.

    When you configure the RAM role, set Account B as the trusted account and authorize the RAM role to access the cloud resources of Account A.

    2. Use Account B that owns the destination instance to log on to the DTS console and configure the data synchronization task. For more information, see the Procedure section of this topic.

    DTS can read the information about the source Tair (Redis OSS-Compatible) instance across Alibaba Cloud accounts.

    Notes

    Type

    Description

    Source database limits

    • To ensure synchronization quality, DTS inserts a key with the prefix `DTS_REDIS_TIMESTAMP_HEARTBEAT` into the source database to record update timestamps. If the source database uses a cluster architecture, DTS inserts this key into each shard. This key is filtered out during synchronization and expires after the sync task ends.

    • If the source database is a read-only instance or the DTS account does not have write (SETEX) permission, the reported latency may be inaccurate.

    • To ensure a stable synchronization link, increase the value of the repl-backlog-size parameter in the redis.conf file.

    • If some keys in the source database use an expiration policy, they might not be deleted immediately after they expire. This can cause the number of keys in the destination database to be smaller than in the source database. You can run the `info` command to check the number of keys.

    • Limits on synchronizing data from a Basic Edition Redis instance to a cluster architecture Redis instance: A cluster allows a command to operate on only a single slot. If you run a command that operates on multiple keys in different slots, the following error occurs:

      CROSSSLOT Keys in request don't hash to the same slot

      During DTS synchronization, run only single-key commands to prevent the synchronization link from breaking.

    • If the source instance is a Tair (Enterprise Edition) instance that uses Persistent Memory as the Storage Medium, ensure that the appendonly parameter is set to yes. For more information, see Procedure.

    Other limits

    • If the source instance is a self-managed Redis instance, run the config set repl-timeout 600 command to set the repl-timeout parameter for replication between the secondary and master databases to 600 seconds. If the source database contains a large amount of data, you can increase the value of the repl-timeout parameter as needed.

    • If the source Redis instance is scaled in or out (shards are added or removed) or its specifications are changed (memory is scaled up) during synchronization, you must reconfigure the task. To ensure data consistency, clear the data in the destination Redis instance before you reconfigure the task.

    • If the source or destination instance is a self-managed Redis instance (the Access Method is not Alibaba Cloud Instance) and its endpoint changes during synchronization, for example, due to instance migration or a primary/secondary failover, the sync task may retry, experience latency, fail, or even cause data inconsistency. Check the status of the sync task promptly. If the DTS task retries, experiences latency, fails, or becomes abnormal, reconfigure the sync task.

    • If an instance migration, such as a primary/secondary failover, is triggered on the destination Redis instance, data might be written only to the memory and not to the secondary database. This can cause data loss.

    • Keep the source and destination database versions the same, or synchronize from an earlier version to a later version to ensure compatibility. If you synchronize from a later version to an earlier version, compatibility issues may occur.

    • During initial full data synchronization, DTS uses some read and write resources on the source and destination databases. This may increase the database load. Before you start data synchronization, evaluate the performance of the source and destination databases. Synchronize data during off-peak hours.

    • During DTS synchronization, do not write data from other sources to the destination database. This causes data inconsistency between the source and destination databases.

    • If the destination instance is deployed in a cluster architecture and the amount of memory used by a shard in the destination instance reaches the upper limit, or if the available storage space of the destination instance is insufficient, the data synchronization task fails due to out of memory (OOM).

    • By default, the maxmemory-policy parameter that specifies how data is evicted is set to volatile-lru for Tair (Redis OSS-compatible) instances. If the destination instance has insufficient memory, data inconsistency may occur between the source and destination instances due to data eviction. In this case, the data synchronization task does not stop running.

      To prevent data inconsistency, we recommend that you set maxmemory-policy to noeviction for the destination instance. This way, the data synchronization task fails if the destination instance has insufficient memory, but data loss can be prevented for the destination instance.

      Note

      For more information about data eviction policies, see What is the default eviction policy?

    • If the TDE feature is enabled for the source or destination instance, you cannot use DTS to synchronize data.

    • If any of the following situations occur during data synchronization, the full data might be synchronized to the destination instance again. This can cause data inconsistency.

      • A transient connection occurs on the source or destination Redis instance, which causes the task to fail to resume from a breakpoint.

      • A primary/secondary failover occurs on the source or destination Redis instance.

      • The endpoint of the source or destination Redis instance changes.

      • The synchronization objects of the DTS instance are modified.

    • If a Tair (Redis OSS-compatible) instance has Transport Layer Security (TLS) encryption enabled, you must connect to DTS using an SSL-encrypted connection. TLSv1.3 is not supported. You cannot connect a Tair (Redis OSS-compatible) instance that has SSL enabled to DTS as a Alibaba Cloud Instance.

    • If a sync instance includes both full and incremental data synchronization tasks, restarting the instance may cause DTS to run the full and incremental tasks again.

    • If an instance fails, DTS helpdesk will try to recover the instance within 8 hours. During the recovery process, operations such as restarting the instance and adjusting parameters may be performed.

      Note

      When parameters are adjusted, only the parameters of the DTS instance are modified. The parameters of the database are not modified. The parameters that may be modified include but are not limited to those described in Modify instance parameters.

    Billing

    Synchronization typeTask configuration fee
    Schema synchronization and full data synchronizationFree of charge.
    Incremental data synchronizationCharged. For more information, see Billing overview.

    Commands that can be incrementally synchronized

    Edition

    Command

    Tair (Redis OSS-compatible) Open-Source Edition

    • APPEND

    • BITOP, BLPOP, BRPOP, and BRPOPLPUSH

    • DECR, DECRBY, and DEL

    • EVAL, EVALSHA, EXEC, EXPIRE, and EXPIREAT

    • 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, and PSETEX

    • 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

    • SWAPDB, UNLINK (These two commands can be synchronized only if the engine version of the source database is Redis 4.0.)

    • XADD, XCLAIM, XDEL, XAUTOCLAIM, XGROUP CREATECONSUMER, and XTRIM

    Tair (Redis OSS-compatible) Enterprise Edition

    • APPEND

    • BITOP, BLPOP, BRPOP, and BRPOPLPUSH

    • DECR, DECRBY, and DEL

    • EVAL, EVALSHA, EXEC, EXPIRE, and EXPIREAT

    • 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, and PSETEX

    • RENAME, RENAMENX, RPOP, RPOPLPUSH, RPUSH, and RPUSHX

    • SADD, SDIFFSTORE, SELECT, SET, SETBIT, SETEX, SETNX, SETRANGE, SINTERSTORE, SMOVE, SPOP, SREM, and SUNIONSTORE

    • UNLINK, ZADD, ZINCRBY, ZINTERSTORE, ZREM, ZREMRANGEBYLEX, ZUNIONSTORE, ZREMRANGEBYRANK, and ZREMRANGEBYSCORE

    • XADD, XCLAIM, XDEL, XAUTOCLAIM, XGROUP CREATECONSUMER, and XTRIM

    Note

    • PUBLISH operations cannot be synchronized.

    • If you run the EVAL or EVALSHA command to call Lua scripts, DTS cannot identify whether these Lua scripts are executed on the destination instance. This is because the destination instance does not explicitly return the execution results of Lua scripts during incremental data synchronization.

    • When DTS runs the SYNC or PSYNC command to transfer data of the LIST type, DTS does not clear the existing data in the destination instance. As a result, the destination instance may contain duplicate data records.

    Preparations

    Use the Alibaba Cloud account that owns the source Tair (Redis OSS-Compatible) instance to log on to the Alibaba Cloud Management console. Create a RAM role and set the Alibaba Cloud account that owns the destination Redis instance as the trusted account. For more information, see Configure RAM authorization for cross-account DTS tasks.

    Procedure

    1. Use the Alibaba Cloud account that owns the destination Tair (Redis OSS-Compatible) instance to go to the Data Synchronization Tasks page in one of the following two ways.

      DTS console

      1. Log on to the DTS console.

      2. In the left-side navigation pane, click Data Synchronization.

      3. In the upper-left corner of the page, select the region in which the data synchronization task resides.

      DMS console

      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.

      1. Log on to the DMS console.

      2. In the top navigation bar, move the pointer over Data + AI and choose DTS (DTS) > Data Synchronization.

      3. From the drop-down list to the right of Data Synchronization Tasks, select the region in which the data synchronization instance resides.

    2. Click Create Task to go to the task configuration page.

    3. Optional. Click New Configuration Page in the upper-right corner of the page.

      Note

      • Skip this step if the Back to Previous Version button is displayed in the upper-right corner of the page.

      • Specific parameters in the new and previous versions of the configuration page may be different. We recommend that you use the new version of the configuration page.

    4. Configure the source and destination databases. The following table describes the parameters.

      Warning

      After you configure the source and destination databases, we recommend that you read the Limits that are displayed on the page. Otherwise, the task may fail or data inconsistency may occur.

      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 Existing Connection

      • If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections.

        Note

        In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list.

      • If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.

      Database Type

      Select Tair/Redis.

      Access Method

      Select Alibaba Cloud Instance.

      Instance Region

      Select the region to which the source apsaradb for Tair (compatible with Redis) instance belongs.

      Replicate Data Across Alibaba Cloud Accounts

      Select Yes.

      Note

      This feature supports cross-site communication, allowing communication between China site accounts and international site accounts.

      Alibaba Cloud Account

      Enter the ID of the Alibaba Cloud account (primary account) to which the source apsaradb for Tair (compatible with Redis) instance belongs.

      RAM Role Name

      Enter the name of the RAM role created in Preparations.

      Instance ID

      Select the ID of the source apsaradb for Tair (compatible with Redis) instance.

      Authentication Method

      Select this parameter based on your business requirements. Password Login is selected in this example.

      Note

      If the Secret-free login is selected, make sure that password-free access over a Tair (Redis OSS-compatible) instance is enabled. For more information about how to enable password-free access over a Tair (Redis OSS-compatible)instance, see Enable password-free access.

      Database Password

      Enter the account and password of the source apsaradb for Tair (compatible with Redis). Enter the password based on the selected account (which must have read permission). If you forget the password, you can reset it. For more information, see Modify or reset the password.

      • If you use the default account whose username is the same as the instance ID, directly enter the password.

      • For a newly created account, the password format is <custom account>:<password>, for example: testaccount:Test1234.

      Note

      This field is optional. If no password is set, you can leave it blank.

      Encryption

      Specifies whether to encrypt the connection to the source database. Select Non-encrypted or SSL-encrypted based on your business requirements.

      Note

      If you set Access Method is not to Alibaba Cloud Instance and select SSL-encrypted for the self-managed Redis database, you must upload a CA Certificate and enter a CA Key.

      Destination Database

      Select Existing Connection

      • If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections.

        Note

        In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list.

      • If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.

      Database Type

      Select Tair/Redis.

      Access Method

      Select Alibaba Cloud Instance.

      Instance Region

      Select the region to which the destination apsaradb for Tair (compatible with Redis) instance belongs.

      Replicate Data Across Alibaba Cloud Accounts

      This example is a cross-account synchronization instance at the source end. Select No here.

      Instance ID

      Select the ID of the destination apsaradb for Tair (compatible with Redis) instance.

      Authentication Method

      Select this parameter based on your business requirements. Password Login is selected in this example.

      Note

      If the Secret-free login is selected, make sure that password-free access over a Tair (Redis OSS-compatible) instance is enabled. For more information about how to enable password-free access over a Tair (Redis OSS-compatible) instance, see Enable password-free access.

      Database Password

      Enter the account and password of the destination apsaradb for Tair (compatible with Redis) instance. Enter the password based on the selected account (which must have read and write permissions). If you forget the password, you can reset it. For more information, see Modify or reset the password.

      • If you use the default account whose username is the same as the instance ID, directly enter the password.

      • For a newly created account, the password format is <custom account>:<password>, for example: testaccount:Test1234.

      Encryption

      Specifies whether to encrypt the connection to the source database. Select Non-encrypted or SSL-encrypted based on your business requirements.

      Note

      If you set Access Method is not to Alibaba Cloud Instance and select SSL-encrypted for the self-managed Redis database, you must upload a CA Certificate and enter a CA Key.

    5. Click Test Connectivity and Proceed in the lower part of the page.

      Note

      • Make sure that the CIDR blocks of DTS servers can be automatically or manually added to the security settings of the source and destination databases to allow access from DTS servers. For more information, see Add DTS server IP addresses to a whitelist.

      • If the source or destination database is a self-managed database and its Access Method is not set to Alibaba Cloud Instance, click Test Connectivity in the CIDR Blocks of DTS Servers dialog box.

    6. Configure the objects to be synchronized.

      1. In the Configure Objects step, configure the objects that you want to synchronize.

        Parameter

        Description

        Synchronization Types

        By default, Incremental Data Synchronization or Full Data Synchronization and Incremental Data Synchronization is selected. If you select the Incremental Data Synchronization for a DTS instance, we recommend that you select Full Data Synchronization at the same time. After the precheck is complete, DTS synchronizes the historical data of selected objects from the source instance to the destination instance. The historical data serves as the basis for subsequent incremental synchronization.

        Synchronization Topology

        Select One-way Synchronization.

        Note

        This parameter is available only if both the source and destination instances are Tair (Enterprise Edition) instances.

        Processing Mode of Conflicting Tables

        • Precheck and Report Errors: checks whether data exists in the destination database. If no data exists in the destination database, the precheck is passed. If data exists in the destination database, an error is returned during the precheck, and the data synchronization instance 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, data loss may occur in the destination database because data records in the source database overwrite the data records that have the same keys in the destination database. Proceed with caution.

        Source Objects

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

        Note

        You can select only databases as the objects to be synchronized. You cannot select keys as the objects to be synchronized.

        Selected Objects

        If you want to select a database to which data is synchronized from DB 0 to DB 255 or filter the data to be synchronized by prefix, you can use the object name mapping feature or the filtering feature. In the Selected Objects section, right-click the database that you want to synchronize. In the Edit Schema dialog box, configure the parameters. For more information, see Map object names and Specify filter conditions.

        Note

        You cannot map multiple object names at a time.

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

        Parameter

        Description

        Dedicated Cluster for Task Scheduling

        By default, DTS schedules the task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data synchronization instances, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.

        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 synchronization 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 this 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 synchronization task. Otherwise, the data synchronization task fails.

        Note

        • If you specify different retry time ranges for multiple data synchronization tasks that have the same source or destination database, the shortest retry time range 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 your earliest opportunity after the source and destination instances are released.

        Retry Time for Other Issues

        The retry time range for other issues. For example, if the DDL or DML operations fail to be performed after the data synchronization task is started, DTS immediately retries the operations within the time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set this parameter to a value greater than 10. If the failed operations are successfully performed within the specified time range, DTS resumes the data synchronization task. Otherwise, the data synchronization 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 Synchronization

        During full data synchronization, DTS uses the read and write resources of the source and destination databases. This may increase the load on the database servers. You can 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 for full data synchronization tasks to reduce the load on the destination database server.

        Note

        You can configure this parameter only if you select Full Data Synchronization for the Synchronization Types parameter.

        Enable Throttling for Incremental Data Synchronization

        Specifies whether to enable throttling for incremental data synchronization. You can enable throttling for incremental data synchronization based on your business requirements. To configure throttling, you must configure the RPS of Incremental Data Synchronization and Data synchronization speed for incremental synchronization (MB/s) parameters. This reduces the load on the destination database server.

        Extend Expiration Time of Destination Database Key

        The extended time period for keys synchronized from the source database to the destination instance to remain valid. Unit: seconds. If specific commands are used, such as the following commands, we recommend that you set this parameter to ensure data consistency.

        Note

        If the extended time period is specified in a scenario that provides you with distributed lock service, you may fail to release the distributed lock in a timely manner.

        EXPIRE key seconds
PEXPIRE key milliseconds
EXPIREAT key timestamp
PEXPIREAT key timestampMs

        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.

        Configure ETL

        Specifies whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values:

        Monitoring and Alerting

        Specifies whether to configure alerting for the data synchronization instance. If the task fails or the synchronization latency exceeds the specified threshold, alert contacts will receive notifications. Valid values:

      3. Click Next Step: Data Verification to configure data verification.

        For more information about how to use the data verification feature, see Configure a data verification task.

    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 synchronization task, DTS performs a precheck. You can start the data synchronization task only after the task passes the precheck.

      • If the data synchronization task fails the precheck, click View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, rerun the precheck.

      • 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 issue. 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. Purchase an instance.

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

      2. On the buy page, configure the Billing Method and Instance Class parameters for the data synchronization task. The following table describes the parameters.

        Section

        Parameter

        Description

        New Instance Class

        Billing Method

        • Subscription: You pay for a subscription when you create a data synchronization instance. The subscription billing method is more cost-effective than the pay-as-you-go billing method for long-term use.

        • Pay-as-you-go: A pay-as-you-go instance is billed on an hourly basis. The pay-as-you-go billing method is suitable for short-term use. If you no longer require a pay-as-you-go data synchronization instance, you can release the instance to reduce costs.

        Resource Group Settings

        The resource group to which the data synchronization instance belongs. Default value: default resource group. For more information, see What is Resource Management?

        Instance Class

        DTS provides instance classes that vary in synchronization speed. You can select an instance class based on your business requirements. For more information, see Instance classes of data synchronization instances.

        Subscription Duration

        If you select the subscription billing method, specify the subscription duration and the number of data synchronization instances that you want to create. The subscription duration can be one to nine months, one year, two years, three years, or five years.

        Note

        This parameter is available only if you select the Subscription billing method.

      3. Read and select Data Transmission Service (Pay-as-you-go) Service Terms.

      4. Click Purchase and Start. In the dialog box that appears, click OK.

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

        Note

        If a DTS instance you configured supports both full data synchronization and incremental data synchronization tasks, that is, the Synchronization Types contains both Full Data Synchronization and Incremental Data Synchronization, Incremental Data Synchronization is displayed.