 Resource pooling

Resource pooling combines provider computing resources to serve multiple consumers, with physical and virtual resources assigned and reassigned according to demand. NIST emphasizes multi-tenant service and some location independence: consumers generally select an abstraction or broad location requirement rather than one permanently assigned physical server.^[ref]

Pooling can improve utilization when consumers' peak demands occur at different times. It also requires isolation and allocation controls so that one consumer cannot read another's data or monopolize all capacity. For example, virtual machines may share a physical host while retaining separate address spaces. The resource pool and the mechanism enforcing its boundaries are distinct design responsibilities.