For services that require high data reliability or financial services that require regulation, RDS provides remote disaster recovery instances to improve data reliability.

Background introduction

RDS achieves real-time synchronization between the master instance and the remote disaster recovery instance through Data Transmission Service (DTS). Both instances are deployed in the master/slave high-availability architecture. If the master node and slave node cannot be connected due to any abrupt event such as natural disasters in the region of the master instance, you can switch the remote disaster recovery instance to the master instance. After the database link address is modified on the application, service access to the application can be quickly recovered.

Through the DTS console, disaster recovery instances can enable synchronization links to support original features such as synchronization object changing, synchronization rate setting, and delay alarming. For details, see the DTS product documentation.

Disaster recovery instances have the following features:

  • Provide independent database connection addresses so that the connections can be independently controlled by user applications.
  • Use the master/slave high-availability architecture.
  • Support hourly billing and can be enabled and disabled out-of-the-box.
  • Support independent whitelist configuration and account management.

Billing

The configuration of an RDS disaster recovery instance is exactly the same as its master instance configuration, data transmission realizes real-time synchronization between the master instance and the remote disaster recovery instance. As a result, creating disaster recovery instances will result in fees of both RDS and DTS. For price details, see ApsaraDB RDS MySQL Pricing and Data Transmission Service Pricing.

Prerequisites

  • Currently, disaster recovery instances support RDS MySQL instances only.
  • When a disaster recovery instance is to be created, the master instance version must be MySQL 5.6 or later. Make a compatibility test before upgrading the master instance version. Alternatively, create a new MySQL 5.6 to copy the data from the master instance to the new instance, then create a disaster recovery instance on the new instance.
  • The master instance that creates the disaster recovery instance must have an intranet IP address.

Limits

Disaster recovery instances do not support the following functions: backup settings, backup recovery, data migration, database management, Internet IP address assignment, and connection address modification.

Operation steps

  1. Log on to the RDS console.
  2. In the upper-left corner, select the region where the target instance is located.选择地域
  3. Find the target instance and click its ID.
  4. On the Basic Information page, click Add Disaster Recovery Instance.
  5. On the Create Synchronization Task page, click Purchase Instance Right Now to purchase a disaster recovery instance.

    Parameter description:

    • Synchronization Task Name: indicates the name of a synchronization task. The default name can be retained.
    • Instance ID (local instance information): indicates the ID of the local instance. The system automatically associates the current instance ID, or you can click an RDS instance under a different Alibaba Cloud account. Fill in an RDS instance ID, database, account number, and the corresponding password.
    • Instance ID (target instance information): indicates the ID of the target instance. Click Buy Now to purchase the disaster recovery instance.
  6. In the target RDS instance purchase window, select the region where the instance is located, and click Buy Now.

    During the purchase of a disaster recovery instance, you can only select a region, and other configuration information is consistent with that of the master instance by default. If there are any disaster recovery instance upgrade requirements, you can create them successfully in RDS Management Console to change configuration of the disaster recovery instance.

    Note It takes minutes to create a disaster recovery instance. Do not close the dialog box during creation. Otherwise, the disaster recovery instance may fail to be created.
  7. After the disaster recovery instance is purchased, the instance ID is automatically added to the target instance ID. Then, click Authorize White List and Next.
  8. The system automatically creates a migration account. After the creation is complete, click Next.
    Note The name is automatically generated for the disaster recovery instance. For DTS synchronization, do not modify or delete the account. Otherwise, a synchronization exception may occur.
  9. Select the objects to be migrated from the source database objects , click > to add the selected objects, and then click Next.
  10. Select the synchronization initialization type and set the synchronization rate, and click Pre-check to start the synchronization.

    Parameter description:

    • Synchronization Initialization: Migrate the structure and data of the synchronization objects from the local instance to the disaster recovery instance, which will be used as the basis for subsequent incremental data synchronization. This parameter has two options: Structure Initialization and Full Data Initialization. Both options must be selected for your first data synchronization.
    • Synchronization Rate: Set the rate of synchronization between the master instance and the disaster recovery instance to protect services on the master instance. The unit is TPS. If this default value of the parameter is retained, the synchronization rate is the upper limit of the DTS performance.
    Note Pre-check failure is described below. If pre-check is passed, go to Step 12.
  11. The system displays the pre-check results.
  12. Click the detection item after the test results is failed. View the failure details to complete the error troubleshooting.
  13. After troubleshooting, select the current synchronization task from Synchronization Task List and click Start.
  14. After the pre-check is passed, click OK. The synchronization task is automatically started.
  15. On the data synchronization list page of DTS, you can query created synchronization tasks and operate such tasks by changing the synchronization object, setting the monitoring alarm, and modifying the synchronization rate. For details, see DTS product documentation.
    Note In order to ensure the real-time performance of disaster backup instance data, do not pause the synchronization task of the disaster recovery instance.