ApsaraDB RDS:Use the cloud migration feature to migrate data between ApsaraDB RDS for PostgreSQL instances

1.1 Create a CEN instance

1. Log on to the CEN console.

2. On the Instances page, click Create CEN Instance.

3. In the Create CEN Instance dialog box, configure the parameters and click OK.

   Parameter	Description
   Name	Enter a name. The name must be 2–128 characters and can contain digits, hyphens (-), and underscores (_). It must start with a letter.
   Description	(Optional) Enter a description. The description must be 2–256 characters and cannot start with http:// or https://.

1.2 Add the source and destination VPCs to the CEN instance

Add both VPCs separately. The following steps show how to add the source VPC. Repeat the steps to add the destination VPC, selecting the corresponding region and network instance each time.

1. On the Instances page, click the ID of the CEN instance you created.

2. On the Basic Information tab, click the icon to the right of the VPC count.

3. On the Connection with Peer Network Instance page, configure the parameters and click OK.

   Parameter	Description
   Instance type	Retain the default value Virtual Private Cloud (VPC).
   Region	Select the region of the instance whose VPC you are adding. For the source instance, select China (Beijing).
   Transit router	No transit routers are available by default. CEN automatically creates one. Select the primary zone and secondary zone for the transit router.
   Resource owner ID	Select Current Account.
   Attachment name	Enter a name for the attachment.
   Network instance	Select the VPC ID of the instance. To find the VPC ID, go to Database Connection in the ApsaraDB RDS console. After selecting the VPC, choose the vSwitches associated with the primary zone and secondary zone of the transit router.

After adding both VPCs, the CEN instance shows both network attachments.

1.3 Purchase a bandwidth plan

1. On the Instances page, click the ID of your CEN instance.

2. On the Basic Information tab, click Bandwidth Plans, then click Purchase Bandwidth Plan (Subscription).

3. Configure the parameters and click Buy Now to complete the purchase.

   Parameter	Description
   CEN ID	The CEN instance is pre-selected. The bandwidth plan is automatically associated with it after purchase.
   Area A	Select an area for cross-region communication. In this example, select Mainland China. Note You cannot change the area after the bandwidth plan is purchased.
   Area B	Select the other area. In this example, select Mainland China.
   Billing method	Retain the default value Pay-By-Bandwidth.
   Bandwidth	Specify the bandwidth in Mbit/s.
   Bandwidth package name	Enter a name for the bandwidth plan.
   Order time	Select a subscription duration. Optionally enable auto-renewal.

After the purchase completes, the bandwidth plan appears on the tab.

1.4 Configure bandwidth for cross-region communication

1. On the Instances page, click the ID of your CEN instance.

2. On the Basic Information tab, click Bandwidth Plans, then click Allocate Bandwidth for Inter-region Communication.

3. On the Connection with Peer Network Instance page, configure the parameters and click OK.

   Parameter	Description
   Instance type	Select Inter-region Connection.
   Region	Select the region of the source instance. In this example, select China (Beijing).
   Transit router	CEN automatically identifies the transit router for the selected region.
   Peer region	Select the region of the destination instance. In this example, select China (Hangzhou).
   Transit router	CEN automatically identifies the transit router for the peer region.
   Bandwidth allocation mode	Select how to allocate bandwidth. Valid values: Allocate from Bandwidth Plan and Pay-By-Data-Transfer. In this example, select Allocate from Bandwidth Plan.
   Bandwidth plan	Select the bandwidth plan associated with your CEN instance. Required only when Bandwidth allocation mode is Allocate from Bandwidth Plan.
   Bandwidth	Enter the bandwidth in Mbit/s.
   Default line type	Select Platinum or Gold. Platinum is only available when Bandwidth allocation mode is set to Pay-By-Data-Transfer.

After the configuration is saved, the cross-region connection appears in the list.

2.1 Add the destination VPC CIDR block to the IP address whitelist

Add the CIDR block of the destination instance's VPC to the source instance's IP address whitelist. For configuration steps, see Configure an IP address whitelist.

To find the VPC CIDR block of the destination instance:

1. Go to the Instances page in the ApsaraDB RDS console and click the destination instance ID.

2. In the left-side navigation pane, click Database Connection. The Network Type field shows the VPC CIDR block.

2.2 Create a privileged account on the source instance

The migration requires a privileged account with the CREATE ROLE, REPLICATION, and pg_monitor permissions. If a privileged account already exists, skip this step.

To create one, see Create an account. Set Account Type to Privileged Account.

3.1 Run the feasibility assessment

1. Go to the Instances page and click the destination instance ID.

2. In the left-side navigation pane, click Cloud Migration/DR Construction, then click the Feasibility assessment tab.

3. In the Configure Scenario and Source Type step, set Scenario to Migration to Cloud and Source to ApsaraDB RDS Instance. Click Next.

4. In the Configure Destination Instance step, click Next.

5. In the Configure Source Instance step, select all listed items and click Next. Complete any listed preparations before proceeding.

6. In the Start Feasibility Assessment step, configure the source instance details.

   Parameter	Description
   Migration task name	Auto-generated. No change needed.
   Source VPC/DNS IP	Internal endpoint of the source instance. See View and change the endpoints and port numbers.
   Port of source instance	Internal port number of the source instance. See View and change the endpoints and port numbers.
   Username	Username of the privileged account on the source instance.
   Password	Password of the privileged account on the source instance.

7. Click Create Feasibility Assessment Task.

After the assessment completes, check the result in the Migration to Cloud section of the Feasibility assessment tab:

• Successful: Proceed to create the cloud migration task.

• Failed: Click View Report in the Actions column and resolve the reported issues. For common errors, see Introduction to cloud migration assessment reports.

3.2 Start the cloud migration task

1. In the left-side navigation pane, click Cloud Migration/DR Construction, then click the Migration to Cloud tab. Click Create Cloud Migration Task.

2. In the Create Cloud Migration Task dialog box, select the successful assessment task from the Associated Assessment Task drop-down list. ApsaraDB RDS automatically fills in Migration Source Type, Source IP/DNS, Source Port, and Username.

3. Click Initiate Migration to Cloud.

3.3 Switch workloads to the destination instance

1. Click the link in the Cloud Migration Phase column to monitor task progress.

2. When the task enters the incremental data synchronization phase, click the switchover button in the Actions column.

3. In the Switchover dialog box, stop writes to the source instance. You can either configure the source instance to accept only read requests, or stop the connected application from writing data. To make the source instance read-only:

   1. Set the rds_force_trans_ro_non_sup parameter to on. See Modify the parameters of an ApsaraDB RDS for PostgreSQL instance.

   2. Run the following SQL statement to terminate all existing sessions:

   SELECT pg_terminate_backend(pid) FROM pg_stat_activity
   WHERE usename not in ('replicator', 'monitor', 'pgsql', 'aurora') AND pid != pg_backend_pid();

4. Select all check boxes and click Switch Now. Wait for the migration to complete.