One embodiment of the present invention provides a system for provisioning physical resources shared by a plurality of jobs. During operation, the system establishes resource-usage models for the jobs, ranks the jobs based on quality of service (QoS) requirements associated with the jobs, and provisions the jobs for a predetermined time interval in such a way that any unused reservations associated with a first subset of jobs having higher QoS rankings are distributed to other remaining jobs with preference given to a second subset of jobs having a highest QoS ranking among the other remaining jobs. Provisioning the jobs involves making reservations for the jobs based on the resource-usage model and corresponding QoS requirements associated with the jobs.