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CLOUD COMPUTING : GOOGLE FILE SYSTEM

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  GOOGLE FILE SYSTEM(GFS) v   The Google File System (GFS) was developed in the late 1990s. It uses thousands of storage systems built from inexpensive commodity components to provide petabytes of storage to a large user community with diverse needs. v   The main concern of the GFS designers was to ensure the reliability of a system exposed to hardware failures, system software errors, application errors, and last but not least, human errors. v   The system was designed after a careful analysis of the file characteristics and of the access models. Some of the most important aspects of this analysis reflected in the GFS design are: ü   Scalability and reliability are critical features of the system; they must be considered from the beginning rather than at some stage of the design. ü   The vast majority of files range in size from a few GB to hundreds of TB. ü   The most common operation is to append to an existing file; random write operations to a file are extremely infreq

CLOUD COMPUTING : CLOUD SERVICES

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  CLOUD COMPUTING AND SERVICE MODELS Ø   Over the past two decades, the world economy has rapidly moved from manufacturing to more   service-oriented. Ø   Cloud computing benefits the service industry most and advances business computing with a new paradigm. Ø   Developers of innovative cloud applications no longer acquire large capital equipment in advance. They just rent the resources from some large datacenters that have been automated for this purpose.   PUBLIC CLOUD: Ø   A public cloud is built over the Internet and can be accessed by any user who has paid for the service.   Public clouds are owned by service providers and are accessible through a subscription. Ø   The providers of the aforementioned clouds are commercial providers that offer a publicly accessible remote interface for creating and managing VM instances within their proprietary infrastructure. Ø   A public cloud delivers a selected set of business processes. The application and infrastructure servic

cloud computing : virtualization

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  VIRTUAL MACHINES AND VIRTUALIZATION OF CLUSTERS AND DATA CENTERS   Implementation Levels Of Virtualization: Ø   Virtualization is a computer architecture technology by which multiple virtual machines (VMs) are multiplexed in the same hardware machine. Ø   The purpose of a VM is to enhance resource sharing by many users and improve computer performance in terms of resource utilization and application flexibility. Ø   The idea is to separate the hardware from the software to yield better system efficiency. Ø   For example, computer users gained access to much enlarged memory space when the concept of virtual memory was introduced. Ø   Similarly, virtualization techniques can be applied to enhance the use of compute engines, networks, and storage.   Levels of Virtualization Implementation: A traditional computer runs with a host operating system specially tailored for its hardware architecture, as shown in Figure . After virtualization, different user applications ma