Server Migration Center (SMC) allows you to migrate incremental data from source servers to Alibaba Cloud. You can specify the time interval between two consecutive incremental migrations. Incremental migration reduces the service downtime and the total time of migration. This topic describes the best practices for incremental migration.

Prerequisites

Background information

  • Make sure that the SMC client is running during migration. If data transfer is interrupted, you can restart the client and the migration task to resume migration.
  • An intermediate instance is created for each incremental migration task to facilitate the migration process. The intermediate instance incurs a small fee. For more information, see Pay-as-you-go. The intermediate instance is released only when the incremental migration task is in the Expired state or when the task is deleted.

(Optional) Step 1: Exclude dynamic data directories

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

To exclude dynamic data directories, perform the following steps. You do not need to stop the services that are running on the source server.

  1. Log on to the source server.
  2. Configure the SMC client to exclude dynamic data directories.
    For more information, see SMC FAQ.

Step 2: Create and start an incremental migration task

You can perform the following steps to create and start an incremental migration task in the SMC console. You do not need to stop the services that are running on the source server.

  1. Log on to the SMC console.
  2. In the left-side navigation pane, click Migration Sources.
  3. Find the source server from which you want to migrate data. Click Create Migration Job in the Actions column.
  4. On the Create Migration Job page, turn on Automatic Incremental Synchronization, and configure the Synchronization Interval and Upperlimit of Reserved Images parameters. Configure other parameters based on your business requirements and then click Create.
    Automatic incremental synchronization

    You can configure the following parameters. For more information about other parameters, see the "Migration task parameters" table in the Create a server migration task topic.

    • Synchronization Interval: the time interval between two consecutive incremental migrations. Minimum value: 1 hour. Maximum value: 7 days.
    • Upperlimit of Reserved Images: the maximum number of reserved images. Valid values: 1 to 10. A new image is generated for each incremental migration. If the total number of images exceeds the upper limit, the earliest unused image is deleted.
    • Execution Method: the method to run the migration task. In this example, Run Now is selected.
    The incremental migration task immediately starts after it is created. Data is migrated in the following way:
    1. During the first incremental migration, SMC migrates all data except the excluded directories and files, and generates a full image. You can use this image to create an instance for verification.
    2. After the first incremental migration is complete, SMC automatically migrates incremental data and generates images at specific points in time based on the synchronization interval.
      Note The image generated for each incremental migration is a full image of the source server at a specific point in time. The image includes the incremental data at the point in time of migration and all earlier migrated data.
      In an image name, CYCLE_X indicates that the image is generated by the Xth incremental migration. For example, if an image name contains CYCLE_2, the image is generated by the second incremental migration, as shown in the following figure. cycle

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

Select an appropriate point in time to stop the services on the source server, and perform the following steps to include the excluded data directories and run the incremental migration task again:

  1. Log on to the source server, stop the services on the source server, and include the excluded data directories.
  2. In the SMC console, manually run the incremental migration task or wait for the task to automatically run. To manually run the incremental migration task, perform the following steps:
    1. On the Migration Jobs page, find the incremental migration task.
    2. Move the pointer over the more icon and select Manual Incremental Migration in the Actions column.
      Manual incremental migration
    3. In the Start Migration Job dialog box, click OK.

Step 4: Complete incremental synchronization

After the last incremental synchronization is complete, perform the following steps to complete the incremental synchronization.
  1. On the Migration Jobs page, find the incremental migration task.
  2. Move the pointer over the more icon and select Complete Incremental Synchronization in the Actions column. adssd
  3. In the Run Incremental Job dialog box, click OK.
    You can also select Perform One Last Synchronization in the Complete Incremental Task dialog box to complete the last incremental synchronization. add56

Result

On the Migration Jobs page, wait until the incremental migration task is complete.
  • If the incremental migration task is in the Pending state, the migration is successful. You can obtain the image that is generated for the last migration. The image contains all the data of the first full migration and each subsequent incremental migration.
  • If the incremental migration task is in the InError state, the migration fails. You must check logs to fix the issue, and then restart the task. For information about common errors and solutions, see Troubleshooting and SMC FAQ.

What to do next

After you obtain the latest full image, you can perform the following operations:
  • Create an instance to verify the image:
    1. On the Migration Jobs page, find the migration task and click Create Instance in the Actions column.
    2. On the Custom Launch tab, the Image section shows the latest full image. Configure other parameters based on your business requirements and purchase the instance. For more information, see Create an instance by using the wizard.
    3. Connect to the instance and check the system of the server. For more information, see the How do I check my system after I migrate a Windows server? or How do I check my system after I migrate a Linux server? section of the SMC FAQ topic.
  • Stop the incremental migration task:
    Note You can stop an incremental migration task only if the task is in the Synchronizing or Pending state.
    1. On the Migration Jobs page, find the migration task, and move the pointer over the more icon in the Actions column.
    2. Select Stop.
    3. In the Pause Migration Job dialog box, click OK.
  • Delete the incremental migration task:
    1. On the Migration Jobs page, find the migration task, and click Delete in the Actions column.
    2. In the Delete Migration Job dialog box, click OK.