ApsaraDB RDS:Migrate an ApsaraDB RDS for PostgreSQL instance across zones

Limits

• If your database system uses local disks, you can migrate only the primary RDS instance across zones in the same region.

• You cannot migrate a serverless RDS instance to another zone. For more information, see Overview.

Billing rules

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

• If your RDS instance uses standard SSDs, the storage type of the RDS instance is automatically upgraded from standard SSD to PL1 ESSD during the migration. After the upgrade, the fees for storage resources remain unchanged.

Impacts

• 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 cross-zone 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 of your RDS instance to connect your application to your RDS instance.

• If an instance switchover occurs during the cross-zone migration, the VIP of your RDS instance changes. We recommend that you use an endpoint rather than an IP address of your RDS instance to connect to the RDS instance and clear the DNS cache of your client in a timely manner. If the client of your application runs 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 to ensure that your application can obtain the new VIP of the RDS instance after the migration.

  Note

  For more information about how to set the TTL in the JVM configuration, see Class InetAddress.

• After the cross-zone migration is complete, you must restart the corresponding running task in DTS.

• If the resource inventory in the zone to which you want to migrate the instance is insufficient, the migration may fail.

• ApsaraDB RDS for PostgreSQL instances that use standard SSDs are no longer available for purchase. If your RDS instance uses standard SSDs, the storage type of the RDS instance is automatically upgraded from standard SSD to PL1 ESSD during the cross-zone migration. For more information, see [EOS/Discontinuation] End of sale for the standard SSD storage type for specific database engines in ApsaraDB RDS from July 01, 2022.

Migration scenarios

Procedure

1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

2. In the Basic Information section, click Migrate Data Across Zones.

   

3. In the dialog box that appears, select the primary zone, secondary zone, and vSwitches, and click Yes.

   Parameters

   Parameter	Description
   Configure Primary Zone	Select destination zones for the primary and secondary RDS instances. If your RDS instance uses local disks, you can migrate only the primary instance across zones in the same region. The secondary instance cannot be migrated across zones. If the RDS instance uses cloud disks, you can migrate the primary and secondary instance across zones separately or at the same time. Examples: The primary RDS instance resides in Singapore Zone A and the secondary RDS instance resides in Singapore Zone B. You can migrate the primary RDS instance to Singapore Zone C and the secondary RDS instance to Singapore Zone D. The primary RDS instance resides in Singapore Zone A and the secondary RDS instance resides in Singapore Zone B. You can retain the primary RDS instance in Singapore Zone A and migrate only the secondary RDS instance to Singapore Zone C. Note If you separately migrate the primary or secondary RDS instance across zones, you need only to configure the zone to which you want to migrate the instance.
   Configure Secondary Zone
   vSwitch in Primary Zone	Select vSwitches in the destination zones for the primary and secondary RDS instances. If no vSwitches are available in the destination zones, create vSwitches. For more information, see Create and manage a vSwitch.
   vSwitch in Secondary Zone
   Switching Time	Switch Now: The switchover is immediately performed. Switchover Within Maintenance Window: The switchover is performed during the specified maintenance window. For more information, see Configure a maintenance window. Take Effect at Specified Time Range: The switchover is performed at a specified point in time.

   After you click Yes, the system starts to replicate the data of your RDS instance to the destination zones. This process does not interrupt the workloads on your RDS instance. After the data is replicated, the system switches your workloads based on the time that is specified by the Switching Time parameter. You can set the Switching Time parameter to Switch Now, Switchover Within Maintenance Window, or Take Effect at Specified Time Range.

   Warning

   The instance is transiently disconnected during the switchover. Make sure that your application is configured to automatically reconnect to your RDS instance.

   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 zones 10 minutes later. As a result, the RDS instance encounters another transient connection. If the database client runs on a JVM, we recommend that you set the 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 the 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 Impacts.

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