IUCTX - The retention policy is a little misleading. It is only possible to set a minimum retention period for a camera (eg. Camera 1 is required to have at least 2 days of video archives). Currently, it is not possible to configure a maximum amount per camera (eg. Camera 1 will not hold more than 1 day of video archives).
You can reference page 38 of the Orchid Core Admin Guide for a more detailed description.