Incremental server migration - Server Migration Center - Alibaba Cloud Documentation Center

Procedure

Step 1: Perform full migration

Import your migration source and configure migration settings without stopping services on the source server. For instructions on specific scenarios:
Enable automatic incremental synchronization in the migration configuration:
- Automatic Incremental Synchronization: Turn on this switch.
- Synchronization interval: Time between synchronizations (1 hour to 7 days). The next synchronization starts after the current one completes plus the configured Synchronization interval.
- Maximum reserved images: Number of images to retain (1 to 10). Each incremental migration generates a new image. When this limit is exceeded, the oldest unused image is deleted.
View the migration result.

When progress reaches 100%, the full migration is complete and a full image is generated. After each synchronization, the status changes to Waiting until the next incremental migration begins.
Note
Available operations:
- Verify the result: In the Actions column, click Create Instance to create an instance from the image for verification.
- Modify the interval: In the Actions column, click Set Automatic Incremental Synchronization. The new interval takes effect after the next synchronization completes.
- Pause the job: In the Actions column, click Create Instance to pause the migration job.
- Cancel the job: In the Actions column, click Cancel Migration.

Step 2: Stop services and run incremental migration

During off-peak hours, stop services on your source server and run another incremental migration.

Note

Each incremental migration produces a full image of the source server at that point, containing all data (new and previously migrated).
When synchronization starts, the job first performs a data comparison. Comparison speed depends on disk I/O and total data volume, not network bandwidth. After comparison, incremental data is transferred at a speed determined by data volume and network bandwidth. Estimate migration time and test data transfer speed.

Log on to the source server and stop services.
In the SMC console, wait for the next automatic synchronization or manually start one.
- Automatic incremental migration
  
  After the first incremental migration completes, SMC automatically runs subsequent migrations at the specified synchronization interval.
- Manual incremental migration
  
  In the Actions column, click Manual Incremental Synchronization. In the Manual Incremental Synchronization dialog box, click OK.

Step 3: Complete incremental synchronization

After the final data synchronization completes, finalize the incremental migration job.

In the Actions column, click Complete Incremental Synchronization.
In the Complete Incremental Job dialog box, click OK.

You can also select Perform One Last Synchronization in the Complete Incremental Job dialog box to run a final data synchronization. This action finalizes the incremental job. After it completes, the job's status changes to Completed and no further incremental synchronizations will occur.
On the Server Migration page, view the real-time status of the migration.

The amount of time required for data transmission is subject to factors such as the data size of the migration source and network bandwidth. Wait until the migration job is complete.

Important

After you click Complete Incremental Synchronization, the job is finalized and cannot run again. No further manual synchronizations are possible. If you need to migrate more data, create a new incremental migration job.

Verify migration result

If the Migration Status is Completed, the migration was successful.
The resulting image contains all source server data at the time of the final synchronization.
- If you set Destination Type to ECS Image:
  Manual verification
  
  In the Actions column, click Create Instance. This action redirects you to the instance creation page in the ECS console, where the custom image is preselected. For more information about how to create an ECS instance, see Create an instance from a custom image or shared image.
  
  Automatic verification
  
  Note
  To use this feature, the instance must have Cloud Assistant installed, and its operating system must support the agent. For more information, see Install Cloud Assistant Agent.
  
  This feature uses the OOS template ACS-SMC-CreateAndVerifyInstance provided by Alibaba Cloud to automatically verify that the image generated by the migration job can be used to create and start an ECS instance.
  
  In the Actions column, click Verify Migration Result.
  
  In the dialog box that appears, review the verification process and click Verify Now.
  
  Alternatively, click Customize Verification Parameters to manually configure verification parameters.
  
  In the Verify Migration Result column, view the verification result.
  
  Verified: The verification was successful. Click View Report to view the verification result.
  
  Not Verified: The verification failed. Click View Cause to view the cause and troubleshoot the issue.
  
  Alternatively, click the icon in the Actions column and then click View Verification Records in OOS Console to view the execution history of the OOS template.
- If you set Destination Type to ECS Instance, click View Destination Instance in the Actions column to open the destination ECS instance page.
After migrating the server, perform the following steps to ensure that your services run correctly:
- Validate the data to ensure its integrity and correctness. For more information, see How do I check the system after migrating a Linux server? or How do I check the system after migrating a Windows server?.
- If applications and services on the source server are not configured to automatically start, manually start them after the migration.
- The IP address changes during the migration. If your services depend on IP address configurations, you must modify settings such as domain name resolution and ICP filing after the migration.
  
  If a domain name is mapped to the source server, remap it to the new public IP address. For more information, see Add a website resolution.
  
  To retain the source server's private IP address, assign it to the new instance after migration.
  
  If the destination is an ECS Image: Specify the private IP address when you create the ECS instance. For more information, see Specify the primary private IPv4 address for the primary ENI when you create an ECS instance.
  
  If the destination is an ECS Instance: If you did not modify the private IPv4 address in the advanced settings of the migration settings step, you can still modify the private IPv4 address of the destination instance after the migration. For more information, see Modify the primary private IPv4 address of the primary ENI for an existing instance.
The migration test failed if the migration job enters the Drill Exception state.
In this case, you need to check the test report, fix the test items that are in the Critical state, and then perform a test again. For more information, see Configure a migration test.
If the Real-time Migration Status is InError, the migration job failed.
Troubleshoot the issue and retry the migration:
1. In the Actions column, click Troubleshoot Errors. Resolve the issue based on the error code and message. For more information, see SMC FAQ and Troubleshooting.
2. After resolving the issue, click Retry Migration Job in the Actions column. The migration resumes from the point of failure.
  
  Important
  If the intermediate instance has been released, you must restart the migration. For more information, see What do I do if I accidentally release the intermediate instance?.

Clean up resources

Migrate to an image

During the migration, SMC creates a temporary pay-as-you-go intermediate instance named No_Delete_SMC_Transition_Instance in your destination Alibaba Cloud account to assist with the migration. The outcome of the migration determines whether you need to manually release the instance:

Successful migration: SMC automatically releases the intermediate instance. No manual cleanup is required.
Migration error: SMC does not release the intermediate instance, which continues to incur charges. To avoid unnecessary charges, you can release the instance in one of the following ways:
- If you no longer need the migration task, click the migration source ID. In the Actions column for the migration task, click Cancel Migration Job to delete the migration task and automatically release the intermediate instance.
- Manually release the intermediate instance.

Migrate to an instance

During the migration, SMC creates a temporary pay-as-you-go intermediate disk named SMC_Temp_Disk and attaches it to the destination instance to assist with the migration. The outcome of the migration determines whether you need to manually release the intermediate disk:

Successful migration: SMC automatically releases the intermediate disk. No manual cleanup is required.
Migration error: SMC does not release the intermediate disk, which continues to incur charges. To avoid unnecessary charges, you can release the disk in one of the following ways:
- If you no longer need the migration task, click the migration source ID. In the Actions column for the migration task, click Cancel Migration Job to delete the migration task and automatically release the intermediate disk.
- Manually release the intermediate disk.