Cross-region replication (CRR) enables the automatic and asynchronous (near real-time) replication of objects across buckets in different OSS regions. It synchronizes operations such as the creation, overwriting, and deletion of objects from the source bucket to the destination bucket.

Background information

This feature meets the requirements of geo-disaster recovery or data replication. Objects in the destination bucket are extra replicas of objects in the source bucket. They have the same object name, object content, and object metadata such as the creation time, owner, user metadata, and object ACL.
For more information about CRR, see Cross-region replication.
  • After CRR is enabled, CRR traffic is generated when you replicate objects between buckets in the source and destination regions. You are charged for the traffic consumed when you use CRR. Each time an object is synchronized, OSS counts the number of requests and calculates charges on a pay-as-you-go basis. For more information, see Billing items and methods.
  • The cross-region replication feature is available between regions in mainland China, between regions outside mainland China, and between China (Hong Kong) and regions outside mainland China.


  1. Log on to the OSS console.
  2. Click Buckets, and then click the name of the target bucket.
  3. Choose Redundancy for Fault Tolerance > Cross-Region Replication (CRR).
  4. Click Enable. In the Cross-Region Replication (CRR) dialog box that appears, configure the parameters listed in the following table.
    Parameter Description
    Source Region The region where the current bucket is located. By default, the source region is automatically specified.
    Source Bucket The name of the current bucket. By default the source bucket is automatically specified.
    Destination Region Select the region where the destination bucket is located. The source and destination buckets for CRR must be located in different regions. Buckets located within the same region cannot synchronize data between each other.
    Destination Bucket Select the destination bucket. The two buckets with CRR enabled cannot synchronize data with other buckets. If you synchronize data from Bucket A to Bucket B, neither Bucket A nor Bucket B can synchronize data with other buckets.
    Applied To Select the source data to synchronize.
    • All Files in Source Bucket: synchronizes all objects from the source bucket to the destination bucket.
    • Files with Specified Prefix: synchronizes the objects whose names contain the specified prefix from the source bucket to the destination bucket. If you have a folder named management in the root directory of a bucket and a subfolder named abc in management. If you want to synchronize objects in the abc folder, enter management/abc as the prefix. You can specify up to five prefixes.
    Operations Selects the synchronization policy.
    • Add/Change: synchronizes only added or changed data from the source bucket to the destination bucket.
    • Add/Delete/Change: synchronizes all data changes such as the creation, overwriting, and deletion of objects from the source bucket to the destination bucket.
    Replicate Historical Data Specifies whether to synchronize historical data.
    • Yes: synchronizes historical data to the destination bucket.
      Notice When historical data is synchronized, objects in the source bucket may overwrite objects in the destination bucket if these objects have the same name. Before you select this option, ensure that the data is consistent.
    • No: synchronizes only changes generated after CRR is enabled to the destination bucket.
    KMS-based Encryption Selects whether to use a CMK to encrypt objects replicated to the destination bucket.
    CMK ID Selects the CMK ID used to encrypt objects replicated to the destination bucket. To use a CMK to encrypt objects, you must create a CMK in the same region as the destination bucket. For more information, see Manage CMKs.
    Note You will be charged for calling API operations when you use CMKs to encrypt or decrypt data.
    RAM Role Name Selects an authorized role to perform encryption.
    • New RAM Role: A new RAM role named kms-replication-oss-0422-kms-test1 is created to perform encryption.
    • AliyunOSSRole: The AliyunOSSRole role is used to perform encryption. If this role does not exist, it is created.
  5. Click OK.
    • After the configuration is complete, it may take three to five minutes for CRR to take effect. Synchronization information is displayed after the source bucket is synchronized.
    • In CRR, data is asynchronously (near real-time) replicated. It takes several minutes to several hours for the data to be replicated to the destination bucket based on the amount of data.