Knowledgebase

What is virtualization?

As the name indicates, virtualization means creating virtual versions of something and not real ones. Virtualization can be done on hardware, operating systems, storage devices, and network resources.

What is Server Virtualization?

Server Virtualization can be defined as the masking of server resources. These resources will include the number and identity of physical servers, processors, and operating systems from the server users. This server virtualization is achieved by using a software application by the server administrator. This software application divides the physical server into multiple isolated virtual environments.

Types of Server Virtualization

Virtual machines run on the physical server and their operating systems can also vary from virtual machine to virtual machine. The OS of the virtual machine is called the guest OS. All these guest OS are being run on the host operating system. Every virtual machine that runs in this manner is completely unaware of other software that’s also running in the same fabric.

Now, we are going to see the different sorts of server virtualization. The different sorts of server virtualization are listed below.

1) Guest OS/Virtual Machine Model

2) Hypervisor Model

3) Para Virtualization Model

4) Full Virtualization Model

5) Hardware Virtualization Model

6) Kernel Base Virtualization Model

7) Shared Kernel Virtualization Model

These are the different server virtualization techniques in use now. Let’s see each of them intimately.

Guest OS/Virtual Machine Model

The Guest OS/Virtual Machine Model is a very common sort of virtualization. In this type, each virtual machine, generally called VM, runs as a separate instance of the OS within the virtualization software and the virtualization software runs in another OS that is actually installed on the hardware. The OS that runs the virtualization software runs is called the Host OS because it provides the environment for virtualization

Hypervisor Model

The next sort of Virtualization is the Hypervisor Model. In this model, there’s a thin layer of software called Hypervisor. It’s otherwise called Virtual Machine Monitor (VMM). The VMM runs on top of the hardware and provides the environment including the required features and services required for smooth operation and execution of virtual machines. The hypervisor identifies traps and responds to protected or privileged CPU instructions made by each virtual machine. The hypervisor is responsible to handle queuing, dispatching, and execution of virtual machines.

Para Virtualization Model

This is also on the hypervisor virtual machine. It imitates trapping-and-emulation overhead with the software implemented virtualization. It requires the guest OS to be recompiled or modified before installation on the virtual machine. It’s done to make sure performance enhancement because the modified guest OS communicates directly with the hypervisor.

Full Virtualization Model

The Full Virtualization Model is very similar to the previous model which is Para Virtualization Model. It contains functionality to emulate the underlying hardware when necessary. The complete Virtualization causes the hypervisor to trap the machine operations the OS uses to read or modify the system’s status or perform the input and output operations. After it’s trapped them, the hypervisor emulates these operations in software and returns status codes according to what the important hardware would deliver. It’s the reason for unmodified operating systems can run on top of the hypervisor.

Hardware Virtualization Model

It is very almost like the Paravirtualization model and therefore the Full Virtualization Model in its operation. It uses a hypervisor technique but it’s only available on systems that support hardware virtualization.

Kernel Base Virtualization Model

The Kernel Base Virtualization Model doesn’t require a hypervisor but instead runs a separate version of the Linux kernel and an associated virtual machine as a user-space process on the physical host. This provides an easy way to run multiple virtual machines on one host.

Shared Kernel Virtualization Model

The Shared Kernel Virtualization Model is otherwise called System Level virtualization or OS Virtualization. It describes various implementations of running multiple, but logically distinct system environments on one instance of an OS kernel. That’s why it’s called the shared kernel virtualization model. It’s also called the shared kernel approach because all the virtual instances shared a common kernel of the host OS.

These are the various sorts of virtualization techniques used at the moment.

If you would like any longer help please contact our support department.