Abstract: A method and apparatus for selectively logically adding storage to a host features dynamically mapping one or more disk volumes to the host using a storage virtualization layer, without affecting an operating system of the host or its configuration. Storage devices participate in storage area networks and are coupled to gateways. A boot port of the host is coupled to a direct-attached storage network that includes a switching fabric. When a host needs storage to participate in a virtual server farm, software elements allocate one or more volumes or concatenated volumes of disk storage, and command the gateways and switches in the storage networks to logically and physically connect the host to the allocated volumes. As a result, the host acquires access to storage without modification to a configuration of the host, and a real-world virtual server farm or data center may be created and deployed substantially instantly.