Cross-Region Replication

US3 provides a cross-region replication feature, where you can choose to bind two Storage Spaces (Buckets) in different regions for file synchronization.

Cross-region replication is the automatic, asynchronous replication of files across different US3 data centers (regions). It replicates operations such as file creation, updates and deletions from the source storage space to the target storage space in a different region.

The cross-region replication feature provides the capability of disaster recovery across regions for storage spaces while meeting your data replication needs. The files in the target storage space are complete replicas of the files in the source storage space, with the same file names and content.

Use Cases

• Compliance requirements: Your data must be required to keep a copy across a certain distance for compliance purposes. Cross-region replication can replicate data between US3 data centers at a distance to meet these compliance requirements.

• Minimize latency: If you have business needs in two different geographic locations, to reduce the latency when accessing files, you can maintain file replicas at the US3 data centers that are closer to your users.

• Data backup and disaster recovery: If you have high requirements for data security and availability, you can enable the backup data in another US3 data center in case of major disasters such as earthquakes, tsunamis, and other force majeure.

• Data replication: For business reasons, you may need to migrate your data from one US3 data center to another.

• Operational reasons: You may have computational resources in two different data centers and you may use cross-region replication to maintain US3 files in these data centers.

Precautions

1. For two storage spaces in sync, since you can operate both storage spaces simultaneously, the copied files may overwrite files with the same name in the target storage space. The file overwrite operation is irreversible. Please set the cross-region replication rules according to your needs to avoid loss of important data.

2. Since cross-region replication uses asynchronous replication, it may take some time for data to be duplicated to the target Bucket, typically ranging from a few minutes to a few hours, depending on the size of the data.

3. Image source retrieval and cross-region replication features cannot be enabled at the same time.

4. If a bucket is configured with a lifecycle policy, the lifecycle configuration will only apply to the current storage space. Files will not be deleted in sync between storage spaces that have cross-region replication enabled.

5. Expenses related to cross-region replication:

• Traffic fees: The cost of traffic on the source end generated when using the cross-region replication feature to sync the data from the source storage space to the target storage space. For traffic fees, please refer to product pricing.
• Request fees: US3 will calculate the number of requests and charge request fees, including the source’s list pull and download requests, and the target’s upload requests. For request fees, please refer to product pricing.

Setting Up Cross-Region Replication Rules

Select the corresponding bucket, enter the management page, and choose the cross-region replication feature.

Click on the Add Rule button to open the Add Cross-Region Replication Rule page.

1. Target region: You can choose the region in which the replica target space is located. The two storage spaces for data synchronization must be in two different regions. Data synchronization cannot be performed between storage spaces in the same region.

2. Target storage space: Choose the target storage space to enable data synchronization. Neither of the two storage spaces for cross-region replication can simultaneously synchronize with any other storage space. For example, if storage space A is set to synchronize data to storage space B, neither A nor B can establish a data synchronization relationship with any other storage space.

After adding a cross-region replication rule, it will take effect by default. The status can be seen in the status bar. You can use other buttons under the operation bar for corresponding enable, disable, and delete operations.

Notes

1. The cross-region replication feature supports real-time data synchronization. It can monitor and synchronize data additions, deletions, and modifications in real time to the storage space in the target region. For a 2MB file, it can achieve minute level information synchronization and ensure the eventual consistency of data on both sides, but not the consistency of intermediate state data.

2. Currently, only the Beijing, Guangzhou, and Shanghai regions support the cross-region replication feature. Other regions will be supported in the future.

3. At present, only files uploaded through an external domain name can trigger the cross-region replication feature.