OSS Replication Time Control (RTC) helps you meet compliance or business requirements for cross-region replication (CRR). For replication tasks that do not involve historical data, RTC takes effect within 15 minutes after it is enabled. For tasks that involve historical data, RTC takes effect about one hour after the historical data is replicated. Once active, OSS replicates 99.99% of new objects within 10 minutes. This feature also provides near real-time monitoring of data replication, which allows you to view various metrics for your replication tasks.
Billing
After you enable RTC, you are charged for data replication traffic. For more information, see RTC fees for cross-region replication.
For a region pair, if the replication SLA is not met and you have not exceeded the bandwidth or QPS limits, you are eligible for compensation according to the monthly SLA. For more information, see Alibaba Cloud International Website Object Storage Service Service Level Agreement.
Limitations
Supported regions
Chinese mainland
RTC is supported for cross-region replication only between the following regions: China (Hangzhou), China (Shanghai), China (Qingdao), China (Beijing), China (Zhangjiakou), and China (Shenzhen).
Regions outside the Chinese mainland
RTC is supported for cross-region replication only between the US (Silicon Valley) and US (Virginia) regions.
Bandwidth limits
Bandwidth limit between any two regions
The bandwidth limit between any two regions (a region pair) is 10 Gbps in the Chinese mainland and 2 Gbps outside the Chinese mainland.
Replication bandwidth limit for a single region
The replication bandwidth limit for a single region is 20 Gbps in the Chinese mainland and 4 Gbps outside the Chinese mainland.
If your business requires higher bandwidth, contact technical support to request a higher limit.
QPS limits
Replication QPS limit between two regions
The QPS limit between any two regions is 10,000 in the Chinese mainland and 5,000 outside the Chinese mainland.
Replication QPS limit for a single region
The replication QPS limit for a single region is 20,000 in the Chinese mainland and 10,000 outside the Chinese mainland.
ImportantThese QPS limits apply to non-sequential writes. The QPS limit for sequential writes is 2,000. If the request rate is too high, replication latency increases. When you upload a large number of objects, avoid using sequential prefixes for filenames. For more information, see OSS performance best practices.
Enable RTC
RTC can be enabled for replication of an entire bucket, objects with a specified prefix, or objects with specified tags.
Monitor RTC replication metrics
After you enable RTC, you can click RTC Metric Monitoring on the right side of a cross-region replication task in the OSS console to view RTC metrics, such as RTC Replication Latency, RTC Amount of Data to Replicate, and RTC Number of Operations to Replicate.
The following table describes the RTC metrics.
Metric | Description |
RTC Replication Latency | The maximum latency of replication operations for the specified task. This value is the recovery point objective (RPO) of the replication task. For example, if the replication latency is 1 minute, OSS RTC ensures that all data written to the source bucket 1 minute ago has been replicated to the destination bucket. In a disaster recovery scenario, you can restore data to its state from one minute ago. |
RTC Amount of Data to Replicate | The total amount of data pending replication to the destination bucket. For example, 800 MB of data is written to the source bucket at 08:00. From 08:00 to 08:01, the CRR feature replicates 600 MB of data. At 08:01, the amount of data pending replication is 200 MB. |
RTC Number of Operations to Replicate | The total number of operations pending replication to the destination bucket. For example:
At 08:01, the number of operations pending replication is 10. |
RTC Write Bandwidth | The write bandwidth of data designated for replication from the source bucket. For example, data with the prefixes
If the replication rule is configured to replicate only data with the |
RTC Write QPS | The QPS of write, modification, and deletion operations for data designated for replication from the source bucket. For example, at 08:00, an object is uploaded, an object ACL is modified, and an object is deleted. The QPS for each operation is described as follows:
If the replication rule replicates only upload and modification operations, the RTC Write QPS is 15. If the replication rule replicates all operations, the RTC Write QPS is 18. Note RTC write operations include the following:
|