IT1115
Exercise 4
Virtual and Cloud Computing 1. There’s a huge difference between client/server and peer-to-peer networks. For instance, a peer-to-peer network has no central server. Each workstation on the network shares its files equally with the others. There’s no central storage or authentication of users. Conversely, there are separate dedicated servers and clients in a client/server network. Through client workstations, users can access most files, which are generally stored on the server. The server will determine which users can access the files on the network. Peer-to-peer networks should be installed in homes or in very small businesses where employees interact regularly. They are inexpensive to set up (comparatively speaking); however, they offer almost no security. On the other hand, client/server networks can become as big as you need them to be. Some support millions of users and offer elaborate security measures. As you can imagine, client/server networks can become very expensive. 2. The main advantages of using virtual machines are Multiple OS environments can exist simultaneously on the same machine, isolated from each other;
Virtual machine can offer an instruction set architecture that differs from real computer’s; Easy maintenance, application provisioning, availability and convenient recovery. The disadvantages of using virtual machines are When multiple virtual machines are simultaneously running on a host computer, each virtual machine may introduce an unstable performance, which depends on the workload on the system by other running virtual machines; Virtual machine is not that efficient as a real one when accessing the hardware. 3. The three platforms for cloud computing are IAAS,PAAS AND SAAS. SaaS applications are designed for end-users, delivered over the web. PaaS is the set of tools and services designed to make coding and deploying those applications quick and efficient. IaaS is the hardware and software that powers it all – servers, storage, networks, operating systems 4. One of the top advantages of Virtualization is that it requires less hardware to run the same type and amount of software which brings down overall costs. Simple data recovery is another great advantage of this technology. For instance, if your virtual server suddenly becomes corrupted you simply delete it and restore it from its virtual backup. You do not need to spend time and effort on restoring your entire system from scratch and then restore it from the latest backup. So a corrupted virtual system can be recovered in mere minutes. Virtualization provides you with a safe platform on which you can test various software configurations and on various platforms prior to deployment. So in effect you can tinker with the software until you get what you exactly want without inadvertently damaging your existing network. Lower energy consumption since you’re running less computer hardware to accomplish the same type of work. Better system security and reliability. Virtualization systems do not crash due to corruption like device drivers or memory issues. Some Disadvantages of Virtualization Even though rare, physical failures when they do happen can be devastating. For instance, if your primary hard disk which contained all your virtual and physical data is suddenly stolen, burnt, broken or corrupted then all your servers both virtual and physical will need to be restored. Virtualization is mainly dependent on processing power and memory. So you’ll need to factor in both much more memory and processing power into your Virtualization strategy. You’ll need to invest in training existing network administrators who do not have the skills to administer a virtual network. When something goes wrong with a virtualized system it requires complex troubleshooting. This requires expertise and experience of working and troubleshooting Virtualization problems.