Computing and Information Systems - Research Publications

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    Reliable Provisioning of Spot Instances for Compute-intensive Applications
    Voorsluys, W ; Buyya, R ; Barolli, L ; Enokido, T ; Xhafa, F ; Takizawa, M (IEEE, 2012)
    Cloud computing providers are now offering their unused resources for leasing in the spot market, which has been considered the first step towards a full-fledged market economy for computational resources. Spot instances are virtual machines (VMs) available at lower prices than their standard on-demand counterparts. These VMs will run for as long as the current price is lower than the maximum bid price users are willing to pay per hour. Spot instances have been increasingly used for executing compute-intensive applications. In spite of an apparent economical advantage, due to an intermittent nature of biddable resources, application execution times may be prolonged or they may not finish at all. This paper proposes a resource allocation strategy that addresses the problem of running compute-intensive jobs on a pool of intermittent virtual machines, while also aiming to run applications in a fast and economical way. To mitigate potential unavailability periods, a multifaceted fault-aware resource provisioning policy is proposed. Our solution employs price and runtime estimation mechanisms, as well as three fault tolerance techniques, namely checkpointing, task duplication and migration. We evaluate our strategies using trace-driven simulations, which take as input real price variation traces, as well as an application trace from the Parallel Workload Archive. Our results demonstrate the effectiveness of executing applications on spot instances, respecting QoS constraints, despite occasional failures.
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    Cost of Virtual Machine Live Migration in Clouds: A Performance Evaluation
    Voorsluys, W ; Broberg, J ; Venugopal, S ; Buyya, R ; Jaatun, MG ; Zhao, G ; Rong, C (SPRINGER-VERLAG BERLIN, 2009)
    Virtualization has become commonplace in modern data centers, often referred as "computing clouds". The capability of virtual machine live migration brings benefits such as improved performance, manageability and fault tolerance, while allowing workload movement with a short service downtime. However, service levels of applications are likely to be negatively affected during a live migration. For this reason, a better understanding of its effects on system performance is desirable. In this paper, we evaluate the effects of live migration of virtual machines on the performance of applications running inside Xen VMs. Results show that, in most cases, migration overhead is acceptable but cannot be disregarded, especially in systems where availability and responsiveness are governed by strict Service Level Agreements. Despite that, there is a high potential for live migration applicability in data centers serving modernInternet applications. Our results are based on a workload covering the domain of multi-tier Web 2.0 applications.
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    A grid workflow environment for brain imaging analysis on distributed systems
    Pandey, S ; Voorsluys, W ; Rahman, M ; Buyya, R ; Dobson, JE ; Chiu, K (WILEY, 2009-11)
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    Brain Image Registration Analysis Workflow for fMRI Studies on Global Grids
    Pandey, S ; Voorsluys, W ; Rahman, M ; Buyya, R ; Dobson, J ; Chiu, K (IEEE, 2009)