Migrate an ApsaraDB RDS for PostgreSQL instance across zones in the same region

Fees

You are not charged for the migration. This applies even if you migrate your RDS instance from one zone to multiple zones.

Precautions

• During the migration, your database service may be unavailable for a short period of time. Make sure that your application is configured to automatically reconnect to your RDS instance
• The migration causes changes to the virtual IP addresses (VIPs) of your RDS instance. We recommend that you use an endpoint rather than an IP address to connect your application to your RDS instance.
• After the migration, you must immediately delete the cached DNS records from the database client. If the database client on which your application runs is deployed on a Java Virtual Machine (JVM), we recommend that you set the time-to-live (TTL) in the JVM configuration to 60 seconds or less. In this case, if the VIP that is bound to the in-use endpoint of your RDS instance changes, your application can re-query the related DNS records to obtain the new VIP. Then, your application can connect to the new VIP.
  Note The following TTL-setting methods are provided for reference:

  • Set the TTL for all JVM-based applications: Set the networkaddress.cache.ttl parameter in the $JAVA_HOME/jre/lib/security/java.security file to 60.
  • Set the TTL only for local applications: Specify the networkaddress.cache.ttl java.security.Security.setProperty("networkaddress.cache.ttl" , "60"); setting in the initialized code of the local applications. This must be completed before you call the InetAddress.getByName() function for the first time or before you establish a network connection.
• The VIP changes temporarily interrupt the availability of DRDS . After the migration is complete, you must immediately update and view the endpoint configuration in the DRDS console.
• If your RDS instance has an ongoing Data Transmission Service (DTS) task, you must restart the task after the migration is complete.

Migration scenarios

Procedure

1. Go to the Basic Information page.
   1. Log on to the ApsaraDB for RDS console. In the left-side navigation pane, click Instances. In the top navigation bar, select the region where your RDS instance resides.
      
   2. Find your RDS instance and click its ID.
2. In the Basic Information section of the page that appears, click Migrate Across Zones.
3. In the dialog box that appears, specify the destination primary zone, the vSwitch in the destination primary zone, and the switching time. Then, click OK.

   After you click OK, ApsaraDB RDS starts to copy the data of your RDS instance to the destination primary zone. This process does not interrupt the workloads on your RDS instance. After all the data is copied to the destination primary zone, ApsaraDB RDS switches the workloads over to the destination primary zone at the specified switching time. You can set the switching time to Migrate Immediately or Switch Within Maintenance Window.

   Note

   • Your RDS instance encounters a transient connection during the switchover process. Make sure that your application is configured to automatically reconnect to your RDS instance. Otherwise, you must manually reconnect your application to your RDS instance after the workloads are switched over to the destination primary zone.
   • If the DNS records cached on the database client are not immediately updated after the migration, some workloads may be switched over to the destination primary zone 10 minutes later. As a result, your RDS instance encounters another transient connection. If the database client runs on a JVM, we recommend that you set the time-to-live (TTL) in the JVM configuration to 60 seconds or less. In this case, if the virtual IP address that is bound to the in-use endpoint of your RDS instance changes, your application can query the related DNS records again to obtain the new virtual IP address. Then, your application can connect to the new virtual IP address. For more information, see the "Precautions" section of this topic.

   

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