Methods, apparatus and computer program products implement embodiments of the present invention that include identifying, by a first computer in communication with a storage system having one or more storage devices, storage resources on the storage system, and defining multiple resource packs, each of the resource packs comprising respective multiple attributes for the storage resources. In response to an inventory request from a second computer in communication with the first computer, each of the resource packs can be conveyed to the second computer. Additionally, upon receiving, from the second computer, an allocation request to allocate a portion of a given resource pack, the portion of the given resource pack can be allocated in response to the request.