1. A system for selecting a preferred design architecture for a multi-tiered architecture based on a service specification, an infrastructure specification, and service requirements, comprising: a design generator receiving the service specification and the infrastructure specification and establishing a candidate design in an explorable partitionable format based thereon; and an availability evaluation engine configured to receive the candidate design and provide an availability estimate for the received design to the design generator; wherein the design generator iteratively evaluates designs in combination with the ability evaluation engine to establish the preferred design; and further wherein said explorable partitionable format comprises at least one from a group comprising: an attribute value expressed as an ordered set; an attribute value expressed as a function; a scalability attribute; a scope of fault attribute; and an availability mechanism.