US Patent 7558858 High availability infrastructure with active-active designs

Methods and systems for managing a multi-tiered computer infrastructure. The infrastructure includes a plurality of functional layers, wherein one of the layers is a resource allocation layer. Each functional layer includes a set of resources that are substantially interchangeable with other resources in the same layer and adapted to be able to operate with any resource in an adjacent layer. The resource allocation layer receives and manages information regarding the status of the resources and allocates the resources to a task in accordance with utilization levels and operability of any particular resource.