A media server for an on-board entertainment system comprising terminals, the server comprising: a memory for storing media content; a distribution module configured to distribute stored media content to terminals; a controller for controlling the storage of media content in the storage module; wherein the controller is configured to collect the numbers of accesses via the terminals to the media content, to calculate the value of a retention parameter relating to each item of media content as a function of said number of accesses, and to automatically trigger the continued retention of said media content in the memory or its deletion as a function of at least said calculated value.