Overview
Inter-cloud replication is a configuration for buckets. You can configure inter-cloud replication rules to automatically and asynchronously replication incremental objects from or to buckets in different storage regions. After you enable inter-cloud replication, COS will accurately replicate the object content (information such as the object metadata and version ID) from the source bucket to the destination bucket, and the replication and the original object will have identical attributes. In addition, object operations, such as adding and deleting an object, in the source bucket, will also be replicated to the destination bucket.
Note:
- To enable the inter-cloud replication feature, you need to ensure that the source and destination buckets are in different storage regions and that the versioning feature is enabled for both buckets.
- When you enable inter-cloud replication, unless you specify to configure a different storage type for the object replica when you replicate the data, the object replication will be of the same storage type as the source object.
- During replication, COS will replicate the access control list (ACL) of the source bucket.
- COS does not support configuring inter-cloud replication rules between two different accounts.
Applicable Scenario
- Remote disaster recovery: COS offers 11 nines of durability for object data, but there is still a slight chance of data loss due to force majeure such as wars and natural disasters. If you want to avoid data loss and explicitly have a separate replication of data in a different region, you can use inter-cloud replication to implement inter-cloud disaster recovery. In this way, when an IDC is damaged due to force majeure, the IDC in another region can still provide data copies for your use.
- Compliance requirements: COS offers methods such as multiple copies and erasure coding in physical disks for data by default to ensure data availability. However, some industries may have compliance requirements stipulating that you preserve data copies across different storage regions. Therefore, enabling inter-cloud replication allows you to replicate data across different storage regions to meet such requirements.
- Reducing access latency: When your end users access your objects from different geographic locations, you can use inter-cloud replication to maintain the object copies in the available storage region closest to your end users' geographic locations. This will minimize your end users' access latency and improve your product experience.
- Special technical requirements: When you have compute clusters in two regions and these clusters need to process the same set of data, you can use inter-cloud replication to maintain object copies in both regions.
- Migrating and backing up data: You can replicate your business data from one available region to another according to the development needs of your business to achieve data migration and backup.
Notes
Limits on Replication Time
The time it takes for COS to replicate an object depends on factors such as the object size, the distance between the storage regions, and the upload method of the object. Based on the above factors, the synchronization time varies from a few minutes to a few hours.
- Object size: It takes more time to replicate larger objects. For them, it is recommended that you use multipart upload to reduce their upload and synchronization time.
- Distance between the storage regions: It takes more data transfer time for a longer distance between the regions.
- Upload method of the object: Simple upload does not support concurrent uploads and can only upload or download data serially over a single connection, but multipart upload supports concurrent uploads. Therefore, using multipart upload for large files will speed up upload and inter-cloud replication.
Notes on Versioning
Inter-cloud replication configuration requires you to configure the versioning feature for both the source and destination buckets. . After you enable versioning, you should note that disabling it will affect the inter-cloud replication feature in the following ways:
- If you try to disable versioning for a bucket where the inter-cloud replication feature is enabled, COS will return an error and prompt you to delete the inter-cloud replication rule before disabling versioning.
- If you try to disable versioning for a destination bucket, COS will prompt you that doing so will affect the inter-cloud replication feature. If you proceed to disable versioning, the inter-cloud replication rule that specifies this bucket as the destination bucket will become invalid in COS.