SMC allows you to migrate incremental data from source servers to Alibaba Cloud. You can specify the time interval between incremental migration tasks. 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.
  • Each incremental migration task creates an intermediate instance 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. Then, you can stop the services on the source server and start the migration task. 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 and exclude dynamic data directories.

Step 2: Create and start an incremental migration task

You can perform the following steps to exclude dynamic data directories. You do not need to stop your 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 Task in the Actions column.
  4. On the Create Migration Task page, turn on the Automatic Incremental Synchronization switch, and set the Synchronization Interval and Upperlimit of Reserved Images parameters. Set other parameters based on your needs and then click OK.
    Automatic incremental synchronization

    You can specify the following parameters. For more information, see the "Migration task parameters" table in the Step 2: Create and start a migration task topic.

    • Synchronization Interval: Specify the time interval between two consecutive incremental migration tasks. Minimum value: 1 hour. Maximum value: 7 days.
    • Upperlimit of Reserved Images: Specify the maximum number of reserved images. Valid values: 1 to 10. Each incremental migration task generates new images. If the total number of generated image files exceeds the upper limit, the earliest unused images are deleted.
    • Method to Run: Select a method to run the migration task. In this example, Run Now is selected.
    The migration task immediately starts after it is created. Then, the migration task enters the Finished or InError state.
    1. The first incremental migration task 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 task is completed, SMC migrates incremental data and generates images at specific points in time based on the specified synchronization interval.
      Note The image generated for each incremental migration task is a full image of the source server at a specific time. The image includes the incremental data and all migrated data.
      In the image names that are generated during incremental migration, CYCLE_X indicates that the image is generated by the Xth incremental migration task. For example, if an image name contains CYCLE_2, it indicates that the image is generated by the second incremental migration task, as shown in the following figure. cycle

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

After you stop the services on the source server, perform the following steps to skip the excluded data directories and run an incremental migration task again:

  1. Log on to the source server. Stop the services that run on the source server and skip 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 Tasks page, find the incremental migration task.
    2. Click the more icon and then choose Manual Incremental Migration in the Actions column.
      Manual incremental migration
    3. In the Start Migration Task message, click OK.

Result

On the Migration Tasks page, wait until the task is completed.
  • If the migration task is in the Waiting state, the migration succeeded and you can obtain the image that was generated during the migration. This image contains all the data of the first full migration and each subsequent incremental migration of the source server.
  • If the migration task is in the InError state, the migration has failed. You must check logs to fix the issue, and then restart the task. For information about common errors and solutions, see 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 Tasks 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 needs 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 destination server. For more information, see How can I check my system after migrating a Windows server? or How can I check my system after migrating a Linux server?
  • Stop the incremental migration task:
    Note You can pause an incremental migration task only when the task is in the Syncing or Waiting state.
    1. On the Migration Tasks page, find the migration task, and click the more icon in the Actions column.
    2. Click Pause.
    3. In the Stop Migration Task message, click OK.
  • Delete the incremental migration task:
    1. On the Migration Tasks page, find the migration task, and click Delete in the Actions column.
    2. In the Delete Migration Tasks message, click OK.