Symptoms
If you change the acceleration region of your CDN service, the following situations may occur:
Increased back-to-origin traffic
After you change the acceleration region from Chinese Mainland Only to Global, Alibaba Cloud CDN uses nodes that are deployed outside the Chinese mainland. These nodes have not cached resources on your origin server. As a result, when users request resources from nodes outside the Chinese mainland, these nodes must retrieve the requested resources from your origin server first. This increases the amount of back-to-origin network traffic within a short period of time.
In this case, you must pay close attention to the status of your origin server in case the origin server is overwhelmed by the increased workload. In most cases, Alibaba Cloud CDN L2 nodes can greatly reduce the amount of back-to-origin network traffic. However, to prevent potential risks, we recommend that you pay attention to the amount of workload on your origin server after you change the acceleration region.
Reduced cache hit ratio
An increased amount of back-to-origin network traffic reduces cache hit ratios within a short period of time.