tencent cloud


Offline Migration

Last updated: 2022-06-29 11:38:27

    This document describes how to migrate your instance and data in an offline manner.


    Supported by TencentCloud Service Migration (CSM), the service migration feature lets you migrate operating systems, applications, and application data from a source server to a Cloud Virtual Machine (CVM) instance or Cloud Block Storage (CBS) instance. It helps meet enterprise needs for cloudification, cross-cloud migration, cross-account or cross-region migration, and hybrid cloud deployment.

    Service Migration provides offline migration and online migration. Offline migration includes:

    • Migrate to CVM allows you to migrate a system disk image (or both system disk image and data disk image if necessary) to a specific CVM instance.
    • Migrate to CBS allows you to migrate a data disk image to a specific cloud disk.


    Activate Tencent Cloud Cloud Object Storage (COS) and make sure COS is available in your region.
    For regions supported by COS, see Regions and Access Endpoints.


    • Supported image formats: QCOW2, VHD, VMDK, and RAW. We recommend using the compressed image format to shorten the transmission and migration time.
    • The image to upload is stored in the COS bucket in the same region as of the destination CVM.
    • The image size cannot be greater than the capacity of the destination disk. For example, to upload a 50 GB image, the system disk must be at least 50 GB.
    • Snapshot files (such as *-00000*.vmdk) are not supported.
    • Create an image of the source server.
    • Windows server: Preparing a Windows Image.
    • Linux server: Preparing a Linux Image.
    • Upload the created image file to COS.
    • For large image files, it is recommended to upload by using the COSCMD tool to prevent upload interruption. For more information, see COSCMD.
    • If images exported from other cloud platforms are compressed packages (such as .tar.gz files), you can upload them directly to COS.
    • Obtain the COS address of the uploaded image.
      Go to the COS console, locate the image file you just uploaded and copy the temporary URL on the image file details page.
    • Prepare the destination CVM or cloud disk.
    • Purchase a CVM instance.
    • View CBS purchase instructions.


    1. Log in to the CVM console and click Service Migration in the left sidebar.
    2. Click Migrate to CVM on the “Offline migration” page.
    3. In the “Migrate to CVM” pop-up window, complete the preparation, and click Next.
    4. Select the region and enter the task name, COS link and the CVM instance to migrate to.
    5. Click Complete.
      During the migration, you can quit or close the Service Migration page. You can also return to this page anytime to check the task progress.
      • The system disk capacity of the target instance cannot be less than the size of the uploaded image file. Otherwise, the task will fail.
      • If you need to import both the system disk images and data disk images, the target instances must be mounted with a corresponding amount of data disks.
      • The capacity of the target disk should be greater than (as recommended) or equal to that of the source disk.


    For more information, see Service Migration.

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