# Cross-Region Backup

Cloud Database MongoDB(NVMe) provides the cross-region backup feature, which stores backup files in another region. It helps users improve regulatory compliance and disaster recovery capabilities, and increases data reliability. Users can enable or disable cross-region backup, set the retention period of the backup files in the target region, view the files that have already been backed up across regions, download backup files, and create clusters from the backup files in the target region.

## Supported Regions

Currently, cross-region backup is supported in the following regions:

| Source Region | Target Region |
|------|------|
| North China (Beijing 2) | East China (Shanghai 2) |
| Taiwan (Taipei) | South Korea (Seoul) |
| South Korea (Seoul) | Japan (Tokyo) |
| Japan (Tokyo) | Taiwan (Taipei) |
| US (Washington) | US (Los Angeles) |
| Vietnam (Ho Chi Minh) | Thailand (Bangkok), Indonesia (Jakarta), Singapore |

## Enable Cross-Region Backup

Before you enable cross-region backup, the target regions available to the cluster are obtained first. You can enable the cross-region backup feature, and set the target region and the retention period (7 days to 5 years).
After the automatic or manual backup of the cluster is completed, the cross-region backup process is triggered, and the completed backup files are synchronized to the target region that you have set. Backup files in the target region that exceed the retention period are deleted.

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## Disable Cross-Region Backup

After you enable cross-region backup for a cluster, you can disable the feature. Note that disabling cross-region backup does not delete the backup files that have already been backed up. These files continue to be managed according to the retention policy. If you no longer need the backup files, you can change the retention period before you disable the feature. Deleting a cluster does not delete the backup files of the cluster in the target region. These files are still retained according to the retention period and incur storage space fees.

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## View Cross-Region Backup Files

After the automatic or manual backup of the cluster is completed, the cross-region backup process is triggered. You can view the relevant backup files in the cross-region backup list of the cluster and in the cross-region backup list of the target region.

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## Download Cross-Region Backup Files

In the target region, for example, if a cluster in North China (Beijing 2) is configured to back up across regions to East China (Shanghai 2), you can view the backup files in the cross-region backup list of East China (Shanghai 2). After you click the Download button, the public download address and the private download address of the file are returned.

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## Restore to a New Cluster from Cross-Region Backup

In the target region, for example, if a cluster in North China (Beijing 2) is configured to back up across regions to East China (Shanghai 2), you can view the backup files in the cross-region backup list of East China (Shanghai 2). Click `Restore to New Instance` to create a new cluster from the backup file. Note the following:

1. The availability zone of the created cluster can only be an availability zone in the current region.
2. The created cluster has no other relationship with the original cluster except that it uses the data files of the original cluster.

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## Billing

The cross-region backup feature incurs the following fees:
Remote storage fee: The remote storage fee is generated by storing backup files in the target region. It is related to the total size of the backup files, and is calculated once every 24 hours. The average storage volume of 24 hours is multiplied by the period of 24. If the storage volume is less than 1 GB, it is charged as 1 GB.
Network traffic fee: The network traffic fee is generated by the network traffic from the region where the cluster resides to the target region of the backup. It is related to the size of the backup files. After the cross-region backup of a file is completed, the fee is calculated immediately. If the backup file size is less than 1 GB, it is charged as 1 GB.