1. A method for controlling content replacement within a content delivery system, the method comprising: setting a content provider specified replacement policy for an edge server of the content delivery system, wherein the replacement policy specifies at least an initial portion of content from the content provider to preload, wherein according to the replacement policy, the edge server preloads only the initial portion of the content to said edge server prior to said content being requested, the initial portion of the content being less than an entirety of the content; and caching content of the content provider at the edge server according to the replacement policy.