HTTP cache hierarchies

In an HTTP cache hierarchy, a Content Gateway node can search a parent cache—which itself can search other caches— before resorting to retrieving the object from the origin server. See Configuring Content Gateway to use an HTTP parent cache.

• You can configure a Content Gateway node to use one or more HTTP parent caches, so that if one parent is unavailable, another parent can service requests. This is called parent failover and is described below.
• If you do not want all requests to go to the parent cache, you can configure the proxy to route certain requests directly to the origin server (for example, requests that contain specific URLs) by setting parent proxy rules in the parent.config configuration file (described in parent.config).
• If the request is a cache miss on the parent, the parent retrieves the content from the origin server (or from another cache, depending on the parent’s configuration). The parent caches the content and then sends a copy to the proxy (its child), (where it is served to the client).