Jose Paulo Xavier Pires

ASTRO: A tool for dependability evaluation of Data Center infrastructures

The advent of cloud computing has demanded more computational resources from data centers in order to provide high-availability services required in this new paradigm. To support data center dependability evaluation, this paper presents a tool, namely, ASTRO, which adopts a hybrid modeling approach, that includes Reliability Block Diagrams (RBD), Stochastic Petri Nets (SPN) and Data Center High-Level models. In addition, this tool also provides a prominent functionality in which an evaluation result can be reused in other models. ASTRO Tool also permits a hierarchical modeling, supporting the piecewise approach proposed by the methodology in which the tool is inserted.

Synthetic workload generation for capacity planning of virtual server environments

Capacity planning tools aim at monitoring and evaluating computational infrastructures resources in terms of workloads. The capacity advisor is a capacity planning tool inside the HP virtual server environment - VSE. This paper describes the development and use of a synthetic workload generator named WGCap (workload generator for capacity advisor), a flexible synthetic workload generator that generates traces to be imported into the capacity advisor for simulating the consumption of resources like CPU demand, memory size, disk data rate and network data rate. The workload generation is reliable and flexible, allowing the generation of workloads based on actual traces or on a significant set of probability distributions and statistical summaries.

Impact analysis of maintenance policies on data center power infrastructure

The growth of engineering disciplines, such as maintainability and reliability, have been motivated by several factors, which include the ever growing of system complexity as well as the high cost associated to failures repairing activities and productivity reduction. This work adopts a methodology, which includes a hybrid modeling technique that considers the advantages of both stochastic Petri nets (SPN) and reliability block diagrams (RBD) to evaluate maintenance policies with different service level agreement (SLA). Dependability, cost and sustainability are also prominent features considered in the proposed methodology.