When Do I Need to Replicate an Image?

Image replication includes in-region replication and cross-region replication.

• In-region replication

  This function is used for conversion between encrypted images and unencrypted images or for enabling advanced features (such as fast creation) for images. For details, see Replicating Images Within a Region.

• Cross-region replication

  This function is used for replicating a private image in the current region to the same account in another region. You can use this private image to deploy the same application environment in the two regions. For details, see Replicating Images Across Regions.

What Images Can I Replicate?

Only private images can be replicated. The restrictions on image replication are as follows:

• In-region replication

  Neither the private images created from ISO files nor the full-ECS images support in-region replication.

• Cross-region replication

  Encrypted images do not support cross-region replication.

Can I Replicate Images Across Regions Between the China Site and International Site?

The China site and International site are accessed by using different accounts. Therefore, you cannot replicate images across regions between the two sites through cross-region replication. However, you can do the replication in the following way:

For example, if you want to replicate a system disk image from the AP-Hong-Kong region of the International site to the CN East-Shanghai1 region of the China site, perform the following operations:

1. Log in to the console of the International site, export the image from the AP-Hong-Kong region to the OBS bucket in the region, and download the image to a local directory. Assume that the image file is exported as Windows Server 2012.qcow2.

   For details, see Exporting Images.

2. Log in to the console of the China site, switch to the CN East-Shanghai1 region, and upload the Windows Server 2012.qcow2 image file to the OBS bucket in the region.

   For details, see Uploading an External Image File.

3. Register the image file as a private image

   For details, see Registering an External Image File as a Private Image.

How Long Does It Take to Replicate an Image?

The time required for replicating an image depends on the network transmission speed and the number of tasks in the queue. Cross-region image replication transfers an image file from a region to another through the network. In normal cases, it takes more than 10 minutes to replicate data of 1 GB across regions.

What Is the Charge for Image Replication?

• In-region replication

  The replicas of system disk and data disk images are stored in OBS buckets for free.

  

  Full-ECS images cannot be replicated within the same region.

• Cross-region replication

  System disk and data disk images: You are charged for the OBS traffic for replicating images cross regions.

  Full-ECS images: You are charged for the CSBS or CBR traffic for replicating images cross regions and also charged for the space used to store the CSBS or CBR backups associated with the replicas.

  

  The process of cross-region full-ECS image replication is as follows:

  1. You replicate the backup of a full-ECS image to the destination region.
  2. In the destination region, the system automatically generates a full-ECS image from the backup.

Is There a Limit on the Image Size During Cross-Region Replication?

Yes. An image to be replicated cannot be larger than 128 GB.

If your image file exceeds 128 GB and you want to replicate it between regions, you are advised to export the image to an OBS bucket, import the image to the OBS bucket in the target region, and register it as a private image.

What Is the Maximum Number of Concurrent Cross-Region Image Replication Tasks?

Five.

How Do I Replicate an Image to a Different Region of Another Account?

Replicate the image to the target region under your account and share it with the target cloud account. Then, the image will be displayed in the shared image list of the target cloud account.

How Do I Replicate an Image Between Subprojects in a Region?

Cross-region image replication allows you to replicate images between regions. Image sharing allows you to replicate images between subprojects in the same region.

In the Share Image dialog box, enter your account name, select the target subproject, and click Add, as instructed in Sharing Specified Images. After the image is shared, switch to the target subproject. On the Image Management Service > Images Shared with Me page, you can view the shared image to be accepted.

How Can I Replicate a Shared Image to Another Region?

Assume that you have accepted an image shared from the CN North-Beijing4 region. If you want to replicate the image to the CN East-Shanghai2 region, perform the following operations:

1. Replicate the shared image as a private image.

   For details, see Replicating a Shared Image.

2. Replicate the private image from CN North-Beijing4 to CN East-Shanghai2.

   For details, see Replicating Images Across Regions.