OMoARcPSD 32795027 MC4203 Cloud Computing cloud computing Anna University MC4203 CLOUD COMPUTING TECHNOLOGIES lOMoARcPSD 32795027 UNIT I DISTRIBUTED SYSTEMS Introduction to Distributed Systems What is distributed system in cloud computing A distributed system is a computing environment in which various components are spread across multiple computers or other computing devices on a network These devices split up the work coordinating their efforts to complete the job more efficiently than if a single device had been responsible for the task A distributed system consists of hardware and software components located in a network of computers that communicate and coordinate their actions only by passing messages Benefits of distributed systems Distributed systems offer a number of advantages over monolithic or single systems including Greater flexibility It is easier to add computing power as the need for services grows In most cases today you can add servers to a distributed system on the fly Reliability A well designed distributed system can withstand failures in one or more of its nodes without severely impacting performance In a monolithic system the entire application goes down if the server goes down Enhanced speed Heavy traffic can bog down single servers when traffic gets heavy impacting performance for everyone The scalability of distributed databases and other distributed systems makes them easier to maintain and also sustain high performance levels Geo distribution Distributed content delivery is both intuitive for any internet user and vital for global organizations Challenges of distributed systems Distributed systems are considerably more complex than monolithic computing environments and raise a number of challenges around design operations and maintenance These include Increased opportunities for failure The more systems added to a computing environment the more opportunity there is for failure If a system is not carefully designed and a single node crashes the entire system can go down MC4203 CLOUD COMPUTING TECHNOLOGIES lOMoARcPSD 32795027 While distributed systems are designed to be fault tolerant that fault tolerance isn t automatic or foolproof Synchronization process challenges Distributed systems work without a global clock requiring careful programming to ensure that processes are properly synchronized to avoid transmission delays that result in errors and data corruption In a complex system such as a multiplayer video game synchronization can be challenging especially on a public network that carries data traffic Imperfect scalability Doubling the number of nodes in a distributed system doesn t necessarily double performance Architecting an effective distributed system that maximizes scalability is a complex undertaking that needs to take into account load balancing bandwidth management and other issues More complex security Managing a large number of nodes in a heterogeneous or globally distributed environment creates numerous security challenges A single weak link in a file system or larger distributed system network can expose the entire system to attack Increased complexity Distributed systems are more complex to design manage and understand than traditional computing environments Risks of distributed systems The challenges of distributed systems as outlined above create a number of correlating risks These include Security Distributed systems are as vulnerable to attack as any other system but their distributed nature creates a much larger attack surface that exposes organizations to threats Risk of network failure Distributed systems are beholden to public networks in order to transmit and receive data If one segment of the internet becomes unavailable or overloaded distributed system performance may decline Governance and control issues Distributed systems lack the governability of monolithic single server based systems creating auditing and adherence issues around global privacy laws such as GDPR Globally distributed environments can impose barriers to providing certain levels of assurance and impair visibility into where data resides Cost control Unlike centralized systems the scalability of distributed systems allows administrators to easily add additional capacity as needed which can also increase costs Pricing for cloud based distributed computing systems are based on usage such as the number of memory resources and CPU power consumed over time If demand suddenly spikes organizations can face a massive bill MC4203 CLOUD COMPUTING TECHNOLOGIES lOMoARcPSD 32795027 Some of the most common examples of distributed systems Telecommunications networks including cellular networks and the fabric of the internet Graphical and video rendering systems Scientific computing such as protein folding and genetic research Airline and hotel reservation systems Multiuser video conferencing systems Cryptocurrency processing systems e g Bitcoin Peer to peer file sharing systems e g BitTorrent Distributed community compute systems e g Folding Home Multiplayer video games Global distributed retailers and supply chain management e g Amazon Characterization of Distributed Systems What is the characterization of distributed system We define a distributed system as one in which hardware or software components located at networked computers communicate and coordinate their actions only by passing messages This simple definition covers the entire range of systems in which networked computers can usefully be deployed Distributed System Characteristics Multiple autonomous components Components are not shared by all users Resources may not be accessible Multiple Points of control Multiple Points of failure Software runs in concurrent processes on different processors MC4203 CLOUD COMPUTING TECHNOLOGIES lOMoARcPSD 32795027 Common Characteristics Certain common characteristics can be used to assess distributed systems Resource Sharing Openness Concurrency Scalability Fault Tolerance Transparency Resource Sharing Heterogeneity by different developers Openness Resource sharing means that the existing resources in a distributed system can be accessed or remotely accessed across multiple computers in the system Computers in distributed systems shares resources like hardware disks and printers software files windows and data objects and data Hardware resources are shared for reductions in cost and convenience Data is shared for consistency and exchange of information In distributed
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