Computing and Information Systems - Research Publications
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ItemOn the effectiveness of isolation-based anomaly detection in cloud data centers(WILEY, 2017-09-25)Summary The high volume of monitoring information generated by large‐scale cloud infrastructures poses a challenge to the capacity of cloud providers in detecting anomalies in the infrastructure. Traditional anomaly detection methods are resource‐intensive and computationally complex for training and/or detection, what is undesirable in very dynamic and large‐scale environment such as clouds. Isolation‐based methods have the advantage of low complexity for training and detection and are optimized for detecting failures. In this work, we explore the feasibility of Isolation Forest, an isolation‐based anomaly detection method, to detect anomalies in large‐scale cloud data centers. We propose a method to code time‐series information as extra attributes that enable temporal anomaly detection and establish its feasibility to adapt to seasonality and trends in the time‐series and to be applied online and in real‐time.
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ItemNo Preview AvailableHolistic resource management for sustainable and reliable cloud computing: An innovative solution to global challenge(Elsevier Inc., 2019-09-01)Minimizing the energy consumption of servers within cloud computing systems is of upmost importance to cloud providers toward reducing operational costs and enhancing service sustainability by consolidating services onto fewer active servers. Moreover, providers must also provision high levels of availability and reliability, hence cloud services are frequently replicated across servers that subsequently increases server energy consumption and resource overhead. These two objectives can present a potential conflict within cloud resource management decision making that must balance between service consolidation and replication to minimize energy consumption whilst maximizing server availability and reliability, respectively. In this paper, we propose a cuckoo optimization-based energy-reliability aware resource scheduling technique (CRUZE) for holistic management of cloud computing resources including servers, networks, storage, and cooling systems. CRUZE clusters and executes heterogeneous workloads on provisioned cloud resources and enhances the energy-efficiency and reduces the carbon footprint in datacenters without adversely affecting cloud service reliability. We evaluate the effectiveness of CRUZE against existing state-of-the-art solutions using the CloudSim toolkit. Results indicate that our proposed technique is capable of reducing energy consumption by 20.1% whilst improving reliability and CPU utilization by 17.1% and 15.7% respectively without affecting other Quality of Service parameters.
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ItemPerformance anomaly detection using isolation-trees in heterogeneous workloads of web applications in computing clouds(John Wiley & Sons Ltd., 2019-10-25)Cloud computing is a model for on-demand access to shared resources based on the pay-per-use policy. In order to efficiently manage the resources, a continuous analysis of the operational state of the system is required to be able to detect the performance degradations and malfunctioned resources as soon as possible. Every change in the workload, hardware condition, or software code can change the state of the system from normal to abnormal, which causes the performance and quality of service degradations. These changes or anomalies vary from a simple gradual increase in the load to flash crowds, hardware faults, software bugs, etc. In this paper, we propose Isolation-Forest based anomaly detection (IFAD) framework based on the unsupervised Isolation technique for anomaly detection in a multi-attribute space of performance indicators for web-based applications. Unsupervised nature of the algorithm and its fast execution make this algorithm most suitable for the environments with dynamic nature where the patterns of data change frequently. The experiment results demonstrate that IFAD can achieve good detection accuracy especially in terms of precision for multiple types of the anomaly. Moreover, we show the importance of validating the accuracy of anomaly detection algorithms with regard to both Area Under the Curve (AUC) and Precision-Recall AUC (PRAUC) in an extensive set of comparisons including multiple unsupervised algorithms. The demonstration of the effectiveness of each algorithm shown by PRAUC results indicates the importance of PRAUC in selecting suitable anomaly detection algorithm, which is largely ignored in the literature.
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ItemETAS: Energy and thermal-aware dynamic virtual machine consolidation in cloud data center with proactive hotspot mitigation(John Wiley & Sons Ltd., 2019-09-10)Data centers consume an enormous amount of energy to meet the ever‐increasing demand for cloud resources. Computing and Cooling are the two main subsystems that largely contribute to energy consumption in a data center. Dynamic Virtual Machine (VM) consolidation is a widely adopted technique to reduce the energy consumption of computing systems. However, aggressive consolidation leads to the creation of local hotspots that has adverse effects on energy consumption and reliability of the system. These issues can be addressed through efficient and thermal‐aware consolidation methods. We propose an Energy and Thermal‐Aware Scheduling (ETAS) algorithm that dynamically consolidates VMs to minimize the overall energy consumption while proactively preventing hotspots. ETAS is designed to address the trade‐off between time and the cost savings and it can be tuned based on the requirement. We perform extensive experiments by using the real‐world traces with precise power and thermal models. The experimental results and empirical studies demonstrate that ETAS outperforms other state‐of‐the‐art algorithms by reducing overall energy without any hotspot creation.
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ItemWorkflow Scheduling Algorithms for Grid Computing(SPRINGER-VERLAG BERLIN, 2008)
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ItemA taxonomy of data grids for distributed data sharing, management, and processing(Association for Computing Machinery (ACM), 2006)Data Grids have been adopted as the next generation platform by many scientific communities that need to share, access, transport, process, and manage large data collections distributed worldwide. They combine high-end computing technologies with high-performance networking and wide-area storage management techniques. In this article, we discuss the key concepts behind Data Grids and compare them with other data sharing and distribution paradigms such as content delivery networks, peer-to-peer networks, and distributed databases. We then provide comprehensive taxonomies that cover various aspects of architecture, data transportation, data replication and resource allocation, and scheduling. Finally, we map the proposed taxonomy to various Data Grid systems not only to validate the taxonomy but also to identify areas for future exploration.