Scheduling Strategies for Cycle Scavenging in Multicluster Grid Systems

The use of today's multicluster grids exhibits periods of submission bursts with periods of normal use and even of idleness. To avoid resource contention, many users employ observational scheduling, that is, they postpone the submission of relatively low-priority jobs until a cluster becomes (largely) idle. However, observational scheduling leads to resource contention when several such users crowd the same idle cluster. Moreover, this job execution model either delays the execution of more important jobs, or requires extensive administrative support for job and user priorities. Instead, in this work we investigate the use of cycle scavenging to run jobs on grid resources politely yet efficiently, and with an acceptable administrative cost. We design a two-level cycle scavenging scheduling architecture that runs unobtrusively alongside regular grid scheduling. We equip this scheduler with two novel cycle scavenging scheduling policies that enforce fair resource sharing among competing cycle scavenging users. We show through experiments with real and synthetic applications in a real multicluster grid that the proposed architecture can execute jobs politely yet efficiently.