Thomas Röblitz

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In this paper, we present an experimental study of deterministic non-preemptive multiple workflow scheduling strategies on a Grid. We distinguish twenty five strategies depending on the type and amount of information they require. We analyze scheduling strategies that consist of two and four stages: labeling, adaptive allocation, prioritization, and(More)
SUMMARY 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(More)
We present an architectural framework for specifying and processing co-reservations in Grid environments. Compared to other approaches, our co-reservation framework is more general. It can be applied to the reservation of applications running concurrently on multiple resources (multi-site applications) and to the planning of job flows, where the components(More)
We present an algorithm for reserving compute resources in a Grid, that allows users to define an optimization strategy , if multiple candidates match the specified requirements. Reservations need not to be exact, but can be elastic in some properties like start-, end-time, duration or the number of requested CPUs. Our algorithm takes the speedup of(More)
This paper discusses the problem of planning resource outsourcing and local configurations for infrastructure services that are subject to Service Level Agreements (SLA). The objective of our approach is to minimize implementation and outsourcing costs for reasons of competitiveness, while respecting business policies for profit and risk. We implement a(More)
We present a framework for the coordinated , autonomic management of multiple clusters in a compute center and their integration into a Grid environment. Site autonomy and the automation of administrative tasks are prime aspects in this framework. The system behavior is continuously monitored in a steering cycle and appropriate actions are taken to resolve(More)
Clusters provide an outstanding cost/performance ratio , but their efficient orchestration, i.e. their cooperative management, maintenance, and use, still poses difficulties. Moreover, many sites operate multiple clusters, each possibly running under a different cluster management system. In this paper, we present an architectural scheme for the coordinated(More)
—Cloud computing effectively implements the vision of utility computing by employing a pay-as-you-go cost model and allowing on-demand (releasing g of IT resources. Small or medium-sized Infrastructure-as-a-Service providers, however, find it challenging to satisfy all requests immediately due to their limited resource capacity. In that situation, both(More)