OSS provides disaster recovery capabilities that support zone-redundant storage (ZRS) and cross-region replication (CRR) for data centers within a region or across multiple regions.
Zone-redundant storage
For regions with three or more availability zones, the multi-zone redundancy storage mechanism is implemented. Multiple copies of your data are stored across multiple zones in the same region, ensuring uninterrupted access even if one zone becomes unavailable. For regions with two availability zones, the dual-zone redundancy storage mechanism is implemented. Copies of your data are redundantly stored across the two zones within the same region, ensuring uninterrupted access even if one zone becomes unavailable.
ZRS supports the following storage classes: Standard, Infrequent Access (IA), and Archive. Dual-zone ZRS is available only for the Standard storage class. The following table describes the differences between the storage classes.
Storage class | Region | Data durability | Service availability | Minimum billable size | Minimum storage duration | Data retrieval fees | Data access | Image processing |
Storage class | Region | Data durability | Service availability | Minimum billable size | Minimum storage duration | Data retrieval fees | Data access | Image processing |
Standard | China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Ulanqab), China (Shenzhen), China (Hong Kong), Japan (Tokyo), Singapore, Indonesia (Jakarta), Germany (Frankfurt) | 99.9999999999% (twelve 9's) | 99.995% | N/A | N/A | N/A | Real-time access with a latency of only milliseconds | Supported |
Malaysia (Kuala Lumpur)① | 99.99% |
Infrequent Access (IA) | China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Ulanqab), China (Shenzhen), China (Hong Kong), Japan (Tokyo), Singapore, Indonesia (Jakarta), Germany (Frankfurt) | 99.50% | 64 KB | 30 days | Based on the size (GB) of retrieved data | Real-time access with a latency of only milliseconds |
Archive | 64 KB | 60 days | Based on the size (GB) of restored data or retrieved Archive data for real-time access | A one-minute restoration process required if real-time access of Archive objects is not enabled Real-time access with a latency of only milliseconds if real-time access of Archive objects is enabled |
①The Malaysia (Kuala Lumpur) region only has 2 zones, so the dual-zone redundancy storage mechanism is implemented for ZRS buckets within. Dual-zone ZRS is available only for the Standard storage class.
CRR
CRR enables the automatic and asynchronous (near real-time) replication of objects across buckets in different OSS regions. Operations, such as the creation, overwriting, and deletion of objects, can be synchronized from a source bucket to a destination bucket.
CRR can meet the following business requirements:
Compliance requirements: Although OSS stores multiple replicas of each object in physical disks, replicas must be stored at a distance from each other to comply with regulations. CRR allows you to replicate data between geographically distant data centers to comply with regulations.
Minimum latency: You have users who are located in two geographical locations. To minimize the latency when the users access objects, you can store replicas of objects in OSS data centers that are geographically closer to these users.
Data backup and disaster recovery: You have high requirements for data security and availability, and want to explicitly maintain replicas of all written data in a second data center. If one OSS data center is damaged in a disaster, such as an earthquake or a tsunami, you can use backup data from the other data center.
Data replication: To ensure the availability of your business, you may need to migrate data across different data centers.
Operational reasons: You have compute clusters deployed in two different data centers that need to analyze the same group of objects. You can store object replicas in the two regions.
CRR can meet your requirements for cross-region disaster recovery and data replication. Objects in the destination bucket are exact replicas of those in the source bucket. They have the same object names, versioning information, object content, and object metadata, such as the creation time, owner, user metadata, and object access control lists (ACLs). CRR can replicate objects that are not encrypted and objects that are encrypted by using SSE-KMS or SSE-OSS at the server side.
For more information, see CRR in OSS Developer Guide.
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