Image Replication

When Do I Need to Replicate an Image?

You can replicate an image within a region or across regions.

• In-region replication

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

• Cross-region replication

  This 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

  Private images created from ISO files or full-ECS images cannot be replicated within a region.

• Cross-region replication

  Encrypted images cannot be replicated across regions.

Can I Replicate Images Across Regions Between the Chinese Mainland, International, and European Websites?

The Chinese Mainland, International, and European websites are accessed by using different accounts. You cannot replicate images between these websites through cross-region replication. However, there is a way to do the replication.

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

1. Log in to the console of the International website, export the image from the CN-Hong Kong region to an OBS bucket in that 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 an Image.

2. Log in to the console of the Chinese Mainland website, switch to the CN East-Shanghai1 region, and upload the Windows Server 2012.qcow2 image file to an OBS bucket in that 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.

How Will I Be Billed for Replicating Images?

• 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 billed for the OBS traffic for replicating images cross regions.

  Full-ECS images: You are billed for the CSBS or CBR traffic generated by replicating the images cross regions and 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. The system replicates 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.

To replicate an image larger than 128 GB across regions, you can export the image to an OBS bucket, import the image to an OBS bucket in the target region, and register it as a private image.

How Many Cross-Region Image Replication Tasks Can I Run Concurrently?

Five.

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

You can use image sharing to replicate images between projects in the same region.

In the Share Image dialog box, enter target project IDs, and click OK, as instructed in Sharing Specified Images. After the image is shared, switch to the target projects. On the Image Management Service > Images Shared with Me page, you can view the shared image to be accepted.

Figure 1 Accepting or rejecting shared images

What Are the Regions That Support Cross-Region Replication of System and Data Disk Images?

Figure 2 Regions that support cross-region replication of system and data disk images

• √ indicates that cross-region replication of system and data disk images is supported.
• × indicates that cross-region replication of system and data disk images is not supported. In this case, export the desired image and then import it to the target region.
• - indicates that the source and destination regions are the same.
• Region adjustment may affect cross-region image replication of users that are registered after the adjustment. In this case, whether the replication can be performed is subject to the management console display. The users that were registered before the adjustment are not affected.
• Regions not listed in the figure above do not support cross-region replication of system or data disk images.

What Are the Regions That Support Cross-Region Full-ECS Image Replication?

If a full-ECS image cannot be replicated to a different region, you can use it to create an ECS, use the ECS to create a system disk image and a data disk image, and replicate the images to the destination region.

A full-ECS image created using an ECS backup can be replicated from the region where they reside to another region, but the replicated full-ECS image cannot be replicated across regions again.