Virtualization refers to the creation of servers, infrastructures, services, and various computing resources on a virtual platform. It is not a new concept, but it is recently being made a feasible option to be used in servers. Here one physical server is converted into different individual and remote virtual spaces which are used up by multiple users as per their respective requirements. Each and every virtual server which is present can further run its own operating system and application independently.
Virtualization changes the hardware and code relations and is one of all the vital components of cloud computing technology that helps to utilize the capabilities of cloud computing to the fullest. It is aforesaid that server virtualization in cloud computing is employed to mask server resources from the server users as this virtualization is achieved through a software application, thereby it screens resources that include the number and identity of the software package, processors, and individual physical servers. It is a process of dividing a physical server into multiple distinctive and isolated virtual servers by utilizing a software application. Also, virtual environments are sometimes called virtual private servers or guests or containers, etc.
There are 3 types of server virtualization which are described as follows:
Hypervisor – It is also known as Virtual Machine Monitor (VMM) which serves as a layer that exists between the operating system and hardware. This software package creates and runs Virtual Machines (VMs) and permits one host computer to support multiple guests’ Virtual Machines by just about sharing its resources, like memory and processing. A hypervisor is a reason for the smooth functioning of multiple operating systems as it provides the necessary features for it. Further, it performs tasks like handling the queues, execution, and return the request of the hardware. It makes it possible to use a lot of a system’s available resources and provide greater IT mobility since the guest Virtual Machines are independent of the host hardware.
There are two types of hypervisors used in server virtualization:
Bare-Metal Hypervisor – It is also known as Type 1 hypervisor which is installed directly on the top of the computing hardware (the host). It manages all the hardware resources which are installed within it, and it controls the hardware and the guest Operating system.
Hosted hypervisor – It is also known as Type 2 hypervisor which is installed as a software application on an existing Operating System and runs directly on top of a conventional Operating System.
Para Virtualization (PV) – It is an enhancement of virtualization technology where the guest operating system (OS) is changed before installing it inside a Virtual Machine to permit all guest Operating systems within the system to share resources among them. Whenever there is similar underlying hardware, then Virtual Machines are easily accessible by the interfaces that are related to those underlying hardware.
By granting the guest Operating System access to the underlying hardware, Para Virtualization permits the communication between the guest Operating System and the hypervisor, thus improving performance and efficiency within the system. This feature reduces the cost and improves the system performance by using VMs that remain underutilized in conventional or full hardware virtualization, thereby resolving issues found in full virtualization. Example – Xen uses paravirtualization.
Full virtualization – Full virtualization is a common and economical option for virtualization and is achieved by a combination of binary translation and direct execution. Through this method, the computer service requests are separated from the physical hardware that facilitates them, and the operating system and their hosted software are run on top of virtual hardware. Also, the VM stimulates enough hardware to permit any unmodified guest Operating System to be run in isolation. Example – VMWare ESX
Hardware-Assisted Virtualization – It is much similar to paravirtualization and full virtualization except that it requires hardware support. Further, no changes in the guest OS are required, and there is a reduction in hypervisor overhead. Example- AMD – V Pacifia and Intel VT Vanderpool.
Kernel level Virtualization – This form of virtualization uses a separate version of the Linux kernel instead of a hypervisor, thereby making it easy for multiple virtual machines are easy to run on a single host. Example – Mode Linux (UML) and Kernel Virtual Machine (KVM).
System-Level or OS Virtualization – It is also called the shared kernel approach since all the virtual machines share a common kernel of the host Operating System. It is a secure method that can host many virtual servers. Example – FreeVPS, Linux Vserver, and OpenVZ.
In server virtualization, the virtual servers are dedicated only to a particular task for their betterment in performance. Every virtual server performs like a distinctive physical device, that is capable of running its own Operating System. Also, software specially designed for this purpose is used. The administrator of the software can convert one physical server into multiple virtual servers. Further, these multiple servers are enough to use all the machines’ processing power. CPU of the computer works with multiple processors which provides the ability to run many complicated tasks with ease.
Server virtualization is a cost-effective method that allows using resources efficiently and provides web hosting services effectively utilizing existing resources of IT infrastructure. Without Server Virtualization, many servers use only a small part of their overall capacity. Therefore, the process of dividing one physical layer into multiple virtual layers acts like a physical server and thus increases the capacity of each physical machine and reduces the major cost of hardware.
This server virtualization in cloud computing divides the volume of the work into multiple servers, and all these virtual servers are capable of performing a particular task. Any individual can reduce the workload between virtual machines according to the load. Server Virtualization helps to address issues at a time which is done by specially designed software, or an administrator that can convert a single physical server into virtual machines.
Some of the benefits/advantages of server virtualization are as follows:
Server virtualization helps businesses that are in IT industries in many ways either by reducing the cost of hardware or providing certain other benefits as stated in the above write-up. Deciding upon both the advantages and disadvantages of server virtualization, the client must choose the type of virtualization as listed above, which shall be best suited for his business to gain the maximum benefits from it.
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