Resource reservations with fuzzy requests

We present a scheme for reserving job resources with imprecise requests. Typical parameters such as the estimated runtime, the start time or the type or number of required CPUs need not be fixed at submission time but can be kept fuzzy in some aspects. Users may specify a list of preferences which guide the system in determining the best matching resources for the given job. Originally, the impetus for our work came from the need for efficient co-reservation mechanisms in the Grid where rigid constraints on multiple job components make it often difficult to find a feasible solution. Our method for handling fuzzy reservation requests gives the users more freedom to specify the requirements and it gives the Grid Reservation Service more flexibility to find optimal solutions. In the future, we will extend our methods to process co-reservations. We evaluated our algorithms with real workload traces from a large supercomputer site. The results indicate that our scheme greatly improves the flexibility of the solution process without much affecting the overall workload of a site. From a user’s perspective only about 10 % of the non-reservation jobs have a longer response time, and from a site-administrator’s view the makespan of the original workload is extended by only 8 % in the worst case.