Virtual machine technologies offer simple and practical mechanisms to address many manageability problems in database systems. For example, these technologies allow for server consolidation, easier deployment, and more flexible provisioning. Therefore, database systems are increasingly being run on virtual machines. This offers many unique opportunities for database research. However, it is also important to understand the cost of virtualization. Virtual machine technologies add a layer of indirection between applications and the hardware that they use (e.g. CPU, memory, disk). This added complexity results in a performance overhead for software systems running in a virtual machine. In this thesis, we present an experimental study of the overhead of running a database workload in a virtual machine. Using a TPC-H workload running on PostgreSQL in a Xen virtual machine environment, we show that Xen does indeed introduce overhead for system calls, page fault handling, and disk I/O. However, these overheads do not translate to a high overhead in query execution time. We show that in all cases the average overhead is less than 10% and, therefore, conclude that the advantages of running a database system in a virtual machine do not come at a high cost in performance.

In the domain of Web Services, it is not uncommon to find redundant services that provide functionalities to the clients. Services with the same functionality can be clustered into a group of redundant services. Respectively, if a service offers different functionalities, it belongs to more than one group. Having various Web Services that are able to handle the client's request suggests the necessity of a mechanism that selects the most appropriate Web Service at a given moment of time. <p>This thesis presents an approach, Virtual Web Services Layer, for dynamic service selection based on virtualization on the server side. It helps managing redundant services in a transparent manner as well as allows adding services to the system at run-time. In addition, the layer assures a level of security since the consumers do not have direct access to the Web Services. <p>Several selection techniques are applied to increase the performance of the system in terms of load-balancing, dependability, or execution time. The results of the experiments show which selection techniques are appropriate when different QoS criteria of the services are known and how the correctness of this information influences on the decision-making process.

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Virtual machines (VMs) are useful mechanisms for better resource utilization, support for special software configurations, and the movement of packaged software across systems. Exploiting VM advantages in a production setting, however, often requires computer systems with the smallest possible disk-size footprint. Administrators and programmers who create VMs, however, may need a robust set of tools for development. This introduces an important conflict: Minimalism demands that packaged software be as small as possible, while completeness demands that nothing required is missing. We present a system called Lilliputia, which combines resource usage monitoring (through a Linux FUSE filesystem we created called StatFS), with a filtered cloning system, which copies an existing physical or virtual machine into a smaller clone. Finally, we show how Lilliputia can reduce the size of the Trellis Network-Attached-Storage (NAS) Bridge Appliance and the Chemical Shift to 3D Structure protein structure predictor to 10-30% of their original size.

Cette thèse vise à interroger la situation de l'individu face à l'horizon virtuel de l'ère interconnectée, ainsi que la créativité surgie du cyberespace. Divisée en deux parties, la première section de cette thèse consiste en une analyse des expériences plastiques, elles-mêmes élaborées en rapport avec les réseaux sous diverses formes : installation, net-art, vidéo, photographie numérique et performance GPS. Les quatre projets artistiques proposés ont ainsi permis une interrogation sur la question du regard, qui, dans le cadre des arts plastiques, traverse à la fois l'auteur, le dispositif et le spectateur. Dans la seconde section,il s'agit de tenter de répondre davantage aux problématiques engagées par ces expériences artistiques. La métaphore du « cycle hydrologique » est d'abord proposée afin de comprendre les réseaux informatiques. Une approche du devenir de l'image du monde est ensuite réalisée à travers un parcours historique sur des cartes géographiques. L'hypothèse proposée est que si ce parcours et cette évolution sont conçus comme la transformation d'une conception mythologique du monde en une représentation rationnelle, l'imaginaire engagé par les cartes numériques peut impliquer à nouveau certaines caractéristiques d'une représentation mythologique. Des phénomènes culturels se trouvant à la frontière du cybermonde sont analysés, dans lesquels les questions du virtuel s'avèrent déterminantes, en particulier celle de la réalité augmentée, de la durée d'immersion virtuelle, de « l'auto-virtualisation » et rejoignent à nouveau l'hypothèse d'une mythologie propre à l'espace-temps virtuel édifié sur les réseaux. / This thesis aims to examine the situation of individuals facing virtual space in the interconnected era and the creativity that emerges in the cyberspace. The thesis is divides into two parts. The first part consists of an analysis of my personal experience in conducting four art projects elaborated in various forms, including installation art, net.art, video art, digital photography and GPS performance art. Regardless of which artistic form is in question, « look » is the key in connecting the author, the audience as well as the visual media. The second part aims to further explore the artistic issues derivated from the personal experience, namely net art, map and virtuality. In order to fulfil this task, the metaphor of « water cycle » is applied to conceptualize the development of internet in a systematic way. In addition, world maps at different stages of human civilization are analyzed to shed light on how the worlview has changed over time. Based on that, a hypothesis is proposed : if the changes in world maps over the course of human history reflects a gradual replacement of a mythological perception of the world by a more rational perspective, the creativity shown in trendy digital maps nowadays might point to a resuscitation of a world view featuring mythological representation. Some cultural phenomena in the cyber space are also analyzed. The focus of the analysis is on a few issues related to virtuality, such as augmented reality, the duration of virtual immersion, as well as « auto-virtualization ». Such analysis should help corroborate the above mentioned hypothesis, namely the rise of mythological representation in virtual space.

The thesis is focused on use and implement High Availability cluster in the productive environment, where is needed to concentrate on business critical application. The main aim of this thesis is to create the environment for callback system, which consist from many software products, for example database, web, java and etc. A company has to consolidate every application in an flexible environment resistent to hardware failure, human error in order to be running 24/7.

El presente trabajo de tesis desarrolla el diseño de una plataforma de virtualización de aplicaciones que pueda atender usuarios locales, externos y móviles de una organización. Esta plataforma de virtualización será diseñada bajo el modelo de disposición en capas y siguiendo los estándares, recomendaciones y buenas prácticas de cada uno de los fabricantes que componen la solución, así como también de metodologías de trabajo como la Gestión de puntos finales unificados (UEM- Unified endpoint management). En el primer capítulo del presente diseño, hablaremos a grandes rasgos de la organización objetivo en el cual se desea plasmar dicho proyecto, así como la situación problemática en el campo de acción de la organización, luego definiremos el objetivo general y sus respectivos objetivos específicos e indicadores. En el segundo capítulo, se presentará el marco teórico, el cual incluirá toda la información referente a las definiciones, normativa y metodología a utilizar. En el tercer capítulo, se realizará el análisis del problema a solucionar con el diseño a proponer, además se identificarán los problemas con la información recabada de la organización, con ello se elaborará el análisis del alcance, impacto y soluciones posibles. En el cuarto capítulo, se mencionan a detalle las especificaciones del diseño multicapas de la plataforma de virtualización de aplicaciones. Y finalmente, se mostrarán los resultados y validaciones, los cuales servirán para demostrar el cumplimiento de los objetivos específicos planteados en el capítulo uno. / This thesis work develops the design of an application virtualization platform that can serve local, external and mobile users of an organization. This virtualization platform will be designed under the layered layout model and following the standards, recommendations and good practices of each of the manufacturers that make up the solution, as well as work methodologies such as EMM (EMM - Enterprise Mobility Management) . In the first chapter of the present design, we will speak in broad strokes of the objective organization in which it is desired to capture said project, as well as the problematic situation in the field of action of the organization, then we will define the general objective and its respective specific objectives and indicators. In the second chapter, the theoretical framework will be presented, which will include all the information regarding the definitions, regulations and methodology to be used. In the third chapter, the analysis of the problem to be solved with the design to be proposed will be carried out, in addition the problems will be identified with the information collected from the organization, with this the analysis of the scope, impact and possible solutions will be elaborated. In the fourth chapter, the multilayer design specifications of the application virtualization platform will be mentioned in detail. And finally, the results will be displayed and validations, which will serve to demonstrate compliance with the objectives specific ones raised in chapter one. / Tesis

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Virtualization technologies have the potential to transform the telemetry post-processing environment. Significant efficiencies can be gained by migrating telemetry post processing activities to virtual computing platforms. However, while facilitating better server utilization, virtualization also presents several challenges; one of the most difficult of those challenges being security. In virtualization, server environments are replicated in software; unfortunately, the security individual servers provide is not replicated in a software stack implementation of a server environment. After reviewing virtualization fundamentals, security issues and their impact on telemetry post processing will be discussed.

Cloud gaming is an application deployment scenario which runs an interactive gaming application remotely in a cloud according to the commands received from a thin client and streams the scenes as a video sequence back to the client over the Internet, and it is of interest to both research community and industry. The academic community has developed some open-source cloud gaming systems such as GamingAnywhere for research study, while some industrial pioneers such as Onlive and Gaikai have succeeded in gaining a large user base in the cloud gaming market. Graphical Processing Unit (GPU) virtualization plays an important role in such an environment as it is a critical component that allows virtual machines to run 3D applications with performance guarantees. Currently, GPU pass-through and GPU sharing are the two main techniques of GPU virtualization. The former enables a single virtual machine to access a physical GPU directly and exclusively, while the latter makes a physical GPU shareable by multiple virtual machines. VMware Inc., one of the most popular virtualization solution vendors, has provided concrete implementations of GPU pass-through and GPU sharing. In particular, it provides a GPU pass-through solution called Virtual Dedicated Graphics Acceleration (vDGA) and a GPU-sharing solution called Virtual Shared Graphics Acceleration (vSGA). Moreover, VMware Inc. recently claimed it realized another GPU sharing solution called vGPU. Nevertheless, the feasibility and performance of these solutions in cloud gaming has not been studied yet. In this work, an experimental study is conducted to evaluate the feasibility and performance of GPU pass-through and GPU sharing solutions offered by VMware in cloud gaming scenarios. The primary results confirm that vDGA and vGPU techniques can fit the demands of cloud gaming. In particular, these two solutions achieved good performance in the tested graphics card benchmarks, and gained acceptable image quality and response delay for the tested games.

Enhancement of network data-plane functionality is an open problem that has recently gained momentum. Addition and programmability of new functions inside the network data-plane to enable high speed, complex network functions with minimum resource utilization, is main focus of this thesis. In this work, we look at different levels of the network data-plane design and using network virtualization and software defined networking we propose data-plane enhancements to achieve these goals. This thesis is divided into two parts, in first part we take a ground up approach where we focus our attention at the fast path packet processing. Using hardware and software based network virtualization we show how hardware and software based network switches can be designed to achieve above mentioned goals. We then present a switch design to quickly add these custom fast path packet processors to the network data-plane using software defined networking. In second part of this thesis we take a top to bottom approach where we present a programming abstraction for network operators and a network function deployment system for this programming abstraction. We use network virtualization and software defined networking to introduce new functions inside the network data-plane while alleviating the network operators of the deployment details and minimizing the network resource utilization.