Migrate incremental data from a server - Server Migration Center

Server Migration Center (SMC) allows you to migrate incremental data from servers to Alibaba Cloud. You can specify the time interval between incremental migration operations. Incremental migration reduces the service downtime and the total duration of cutover. This topic describes how to migrate incremental data from a server.

Procedure

Step 1: (Optional) Exclude dynamic data directories

To ensure stable migration, we recommend that you exclude dynamic data directories, such as the data directories of large databases, before you start an incremental migration job. Later, you can stop the services on the source server and migrate the excluded data directories. Skip this step if you do not need to exclude dynamic data directories from migration.

You do not need to stop the services that are running on the source server when you run an incremental migration job after dynamic data directories are excluded. For more information, see the "How do I exclude files or directories from a migration job?" section of the FAQ topic.

Step 2: Create an incremental migration job

After you import the information about a migration source, create an incremental migration job. You do not need to stop the services that are running on the source server. For more information about the operations for different migration scenarios, see the following topics:

When you create a migration job, turn on Automatic Incremental Synchronization in the Advanced Settings section.

Configure the following parameters related to automatic incremental migration:
- Automatic Incremental Synchronization: specifies whether to enable automatic incremental migration. Turn on this switch.
- Synchronization Interval: the time interval between two consecutive incremental migration operations. You can specify a time interval in the range of one hour to seven days.
- Maximum Reserved Images: the maximum number of images that can be retained during incremental migration. Valid values: 1 to 10. An image is generated for each incremental migration operation. If the total number of images exceeds the upper limit, the earliest unused image is deleted.
The migration job immediately starts after it is created. Data is migrated in the following way:
1. During the first incremental migration operation, SMC migrates all data except the excluded directories and files, and generates a full image. You can use this image to create an Elastic Compute Service (ECS) instance for verification.
2. After the first incremental migration operation is complete, SMC automatically migrates incremental data and generates images at specific points in time based on the value of the Synchronization Interval parameter.
  Note
  The image generated for each incremental migration operation is a full image of the source server at a specific point in time. The image contains the incremental data at the point in time of migration and all earlier migrated data.
3. After an incremental migration operation is complete, the migration job enters the Waiting state and runs at the next specified point in time to migrate incremental data.
Optional. You can also manually run the incremental migration job that is in the Waiting state. Perform the following steps:
1. On the OS Migration page, find the migration job that you want to run and click Manual Incremental Synchronization in the Actions column.
2. In the Manual Incremental Synchronization message, click Confirm.
  Note
  If you want to pause an incremental migration job, find the migration job, move the pointer over the icon in the Actions column and select Pause.
  If you want to delete an incremental migration job, find the migration job, move the pointer over the icon in the Actions column and select Delete.
3. View the incremental migration result.
  If the migration progress is 100%, the incremental migration is complete.

Step 3: Stop the services on the source server and run the incremental migration job again

Stop the services on the source server during off-peak hours, include the excluded data directories, and then run the incremental migration job again. Perform the following steps:

Log on to the source server, stop the services on the source server, and then include the data directories that are excluded in Step 1.
In the SMC console, manually run the incremental migration job or wait for the job to automatically run.
Note
SMC automatically runs the incremental migration job based on the value of the Synchronization Interval parameter.

Step 4: Complete incremental migration

After the last incremental migration operation is complete, perform the following steps to complete incremental migration.

On the OS Migration page, find the migration job that you want to manage and click Complete Incremental Synchronization in the Actions column.
In the Run Incremental Job dialog box, click OK.
You can also select Perform One Last Synchronization in the Run Incremental Job dialog box to perform the last incremental migration operation.
On the Migration Jobs page, view the status of the created job.
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 complete incremental migration, no more incremental migration operations are automatically performed and you cannot manually run the migration job. If you click Complete Incremental Synchronization and confirm the completion by accident but still need to migrate incremental data, you can create an incremental migration job again.

Verify the migration result

If the migration job enters the Completed state, the migration is successful.
You can obtain the data that is generated for the last migration operation. The data contains all the data migrated by the first full migration operation and each subsequent incremental migration operation.
- If you set the Destination Type parameter to ECS Image for the migration job, you can verify the migration result in the following way:
  (Recommended) Manually verify the migration result
  You can click Create Instance in the Actions column to go to the ECS instance creation page in the ECS console. The custom ECS image created by the migration job is selected by default for you to create an ECS instance. For more information, see Create an instance by using a custom image.
  Use the automatic migration result verification feature
  Note
  To use this feature, you must install the Cloud Assistant plug-in in your instance, and the system version of the instance must support this feature. For more information, see Install Cloud Assistant Agent.
  This feature uses the ACS-SMC-CreateAndVerifyInstance template provided by Alibaba Cloud CloudOps Orchestration Service (OOS) to automatically verify whether the image generated by the migration job can be used to create an ECS instance and whether the ECS instance can start as expected.
  Click Verify Migration Result in the Actions column.
  In the dialog box that appears, read the instructions on the verification process and click Verify Now.
  You can also click Customize Verification Parameters to configure the parameters.
  In the Verify Migration Result column, view the verification result. Valid values:
  Verified: indicates that the migration is successful. You can click Show Output Parameters to check the details.
  Not Verified: indicates that the migration failed. You can click View Cause to troubleshoot the failure.
  You can also click the icon in the Actions column and select View Verification Records in OOS Console to view the template history.
- If you set the Destination Type parameter to ECS Instance for the migration job, you can click View Destination Instance in the Actions column to go to the details page of the destination ECS instance to verify the migration result.
After the server is migrated, you must perform the following operations to ensure normal operation of your business:
- Verify the integrity and correctness of the data. For more information, see the How do I check my system after I migrate a Linux server? or How do I check my system after I migrate a Windows server? section of the "FAQ" topic.
- Manually start the applications and services after the migration if automatic start is not enabled for the applications and services on the source server.
- Change the IP address of the server after the migration if your business involves IP address configuration.
  If a domain name has been bound to the source server, the public IP address of the server is changed after the migration. In this case, you must resolve the domain name to the new public IP address of the server For more information, see Add an A record for a website domain name.
  If you want to keep the private IP address unchanged, you can modify the private IP address after the migration is complete. For more information, see Modify the private IP address of an 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.
The migration failed if the migration job enters the InError state.
In this case, you need to perform the following operations:
1. Click Troubleshoot Errors in the Actions column and fix the failure based on the error code and error message. For more information, see FAQ about Server Migration Center (SMC) and Troubleshooting.
2. On the Migration Jobs page, click Retry Migration Job.
  The migration job resumes from the point where it was suspended.
  Important
  If the intermediate instance is released, you must create another migration job. For more information, see the What do I do if I release an intermediate instance by accident? section of the "FAQ" topic.

Clear resources

Migrate a server to an ECS image
During the migration, SMC creates a temporary pay-as-you-go intermediate instance named No_Delete_SMC_Transition_Instance within the destination Alibaba Cloud account. The method to clear resources depends on whether the migration is successful.
- If the migration is successful, the intermediate instance is automatically released. No manual operation is required.
- If the migration failed, the intermediate instance is not automatically released and incurs fees as long as the migration job exists. You can release the intermediate instance in one of the following ways to reduce costs:
  - If you no longer need the migration job, choose > Delete in the Actions column to delete the migration job and release the intermediate instance at a time.
  - Manually release the intermediate instance. For more information, see Release an instance.
Migrate a server to an ECS instance
During the migration, SMC creates a temporary pay-as-you-go intermediate cloud disk named SMC_Temp_Disk in the destination instance. The method to clear resources depends on whether the migration is successful.
- If the migration is successful, the intermediate cloud disk is automatically released. No manual operation is required.
- If the migration failed, the intermediate cloud disk is not automatically released and incurs fees as long as the migration job exists. You can release the intermediate cloud disk in one of the following ways to reduce costs:
  - If you no longer need the migration job, choose > Delete in the Actions column to delete the migration job and release the intermediate cloud disk at a time.
  - Manually release the intermediate cloud disk. For more information, see Release a disk.