Migrate an ApsaraDB RDS for PostgreSQL instance from one zone to another within the same region. After migration, the instance attributes, configuration, and endpoints remain unchanged. Migration duration depends on data volume and typically takes a few hours.
The instance experiences a transient disconnection during the switchover. Configure your application for automatic reconnection before you start the migration.
Prerequisites
Before you begin, make sure that:
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The region where your RDS instance resides has multiple zones. For more information, see Regions and zones.
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Your RDS instance is a primary RDS instance with no read-only RDS instances attached.
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Your RDS instance is in the Running state.
RDS instances that run RDS Cluster Edition cannot be migrated across zones.
Limitations
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If your database system uses Premium Local SSDs, only the primary RDS instance can be migrated across zones in the same region.
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Serverless ApsaraDB RDS instances cannot be migrated to another zone. For more information, see Overview.
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If your RDS instance uses Premium Enterprise SSDs (ESSDs) and the I/O acceleration feature is enabled, the instance cannot be migrated to a zone that does not support I/O acceleration. For more information about supported regions and zones, see Support range. To proceed with the migration, disable I/O acceleration first.
Impacts
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Transient disconnection: The instance is briefly unavailable during the switchover. Configure your application for automatic reconnection.
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Virtual IP address (VIP) changes: Cross-zone migration changes the VIPs of your RDS instance. Use an endpoint rather than an IP address to connect your application to the RDS instance.
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DNS cache invalidation: If a switchover occurs during migration, the VIP changes. Clear the DNS cache on your database client promptly. For applications running on a Java virtual machine (JVM), set the time-to-live (TTL) in the JVM configuration to 60 seconds or less so the application can resolve the new VIP after migration. For more information, see Class InetAddress.
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Delayed DNS update: If DNS records cached on the database client are not updated immediately after migration, some workloads may be switched to the destination zones 10 minutes later, causing another transient disconnection.
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Data Transmission Service (DTS) tasks: After migration, restart any running tasks in DTS.
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Insufficient resources: If the resource inventory in the destination zone is insufficient, the migration may fail.
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Storage type upgrade: ApsaraDB RDS for PostgreSQL instances that use standard SSDs are no longer available for purchase. If your instance uses standard SSDs, the storage type is automatically upgraded from standard SSD to PL1 ESSD during migration. Storage fees remain unchanged after the upgrade. 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.
Billing
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Cross-zone migration is free of charge, even when migrating from one zone to multiple zones.
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If your RDS instance uses standard SSDs, the storage type is automatically upgraded from standard SSD to PL1 ESSD during migration. Storage fees remain unchanged after the upgrade.
Migration scenarios
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Migration type |
Scenario |
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One zone to another zone |
The original zone cannot ensure service performance due to issues such as heavy loads. |
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One zone to multiple zones |
Deploy the primary and secondary RDS instances in different zones for cross-zone disaster recovery. This protects your database system against data center failures. For database systems with primary and secondary RDS instances, select the multi-zone deployment method. |
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Multiple zones to one zone |
Use specific features that are supported only with single-zone deployment. |
Procedure
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.
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In the Basic Information section, click Migrate Data Across Zones.
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In the dialog box, configure the following parameters and click Yes.
Parameter
Description
Configure Primary Zone / Configure Secondary Zone
Select destination zones for the primary and secondary RDS instances. The zone selection behavior depends on the storage type:
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Premium Local SSDs: Only the primary instance can be migrated. The secondary instance stays in its current zone.
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Cloud disks: Migrate the primary and secondary instances separately or at the same time. For example, if the primary RDS instance is in Singapore Zone A and the secondary is in Singapore Zone B, migrate the primary to Singapore Zone C and the secondary to Singapore Zone D. Alternatively, keep the primary in Singapore Zone A and migrate only the secondary to Singapore Zone C. If you migrate only one instance, configure only the zone for that instance.
vSwitch in Primary Zone / vSwitch in Secondary Zone
Select vSwitches in the destination zones for the primary and secondary RDS instances. If no vSwitches exist in the destination zones, create them first. For more information, see Create and manage a vSwitch.
Switching Time
Select when to perform the switchover:
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Switch Now: The switchover is performed immediately.
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Switchover Within Maintenance Window: The switchover is performed during the specified maintenance window. For more information, see Configure a maintenance window.
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Take Effect at Specified Time Range: The switchover is performed at a specified point in time.
After you click Yes, the system starts replicating data to the destination zones. This process does not interrupt your workloads. After data replication completes, the system performs the switchover based on the Switching Time setting.
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API reference
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API |
Description |
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Migrates an RDS instance across zones. |