The option is in the test mode at the moment.
What is Origin Shielding
Origin Shielding is one of the ways that G-Core CDN helps to protect your origin server from an overload of requests from multiple CDN nodes.
This service accumulates all customer requests at a special G-Core server. It means that we route all pull requests through a specific server called shield or pre-cache server and this server pull the content from your origin.
How does it protect your origin server
The benefit of this service is that your origin will receive a lower volume of requests for content from a CDN as the aggregation process automatically de-duplicates identical requests and serves the content out of the CDN cache. With Site Shielding enabled, the CDN will make a request for content from a customer’s origin server only when the shield server does not have the content.
How to enable a shield server
In the CDN Resource settings navigate to the Origin Shielding tab and slide Enable Origin Shielding to the right. Choose the location for the pre-cache server. In most cases, you need to choose the closest location to your origin server.