In the article on Virtualization, we tried throwing light on how every element of the Information Technology infrastructure can be virtualized.
But, in the real world, most organizations do not attempt to virtualize all elements of their infrastructures at once. Several organizations start with Server Virtualization and go on to implement a certain level of efficiency improvements. Further, other components may be virtualized as the need arises to improve overall system efficiency and performance.
In this article, we will discuss Server Virtualization.
What is Server Virtualization
Server virtualization is the process of creating multiple distinct and independent virtual servers from a single physical server. This is done by means of a software application. Each of these virtual servers has the ability to run its own operating systems in an isolated state.
The hardware and resources of a machine like the RAM (random access memory), CPU(central processing unit), network controller, and hard drive, they all can be logically split into a series of virtual machines. In fact, each of these virtual machines runs its own different applications and OS(operating system).
Let’s see how Server Virtualization actually works.
How Server Virtualization works
A virtual machine is a kind of software representation of a physical machine. It can execute and perform the same functions that are done by a physical machine. A thin layer of software is inserted into the hardware that contains a virtual machine monitor. This virtual machine monitor is also known as a hypervisor.
The hypervisor can be considered as the technology that manages traffic between virtual machines and physical machines. Server virtualization employs the hypervisor to efficiently use the physical resources. The task of installation, configuration, and administration is associated with setting up these virtual machines. This involves license management, network management, and workload administration, as well as capacity planning.
Server virtualization executes by creating aliases of the computer's hardware from all the software that might run on that specific hardware. The creation of aliases of the physical hardware is called abstraction. This abstraction is achieved by the hypervisor.
Types of Server Virtualization
On the basis of how virtual servers can be created, there are three types of Server Virtualization.
Full Virtualization or Virtual Machine Model
In full virtualization, the guest operating system(OS) is completely isolated by the virtual machine from the hardware and virtualization layer. It uses binary translation and the direct approach technique. Examples of Full Virtualization are Microsoft and Parallel Systems.
Para Virtualization or Paravirtual machine model
Paravirtualization is the kind of CPU virtualization that employs hypercalls for operations to handle instructions during compile time. In paravirtualization, the guest operating system( OS) is partially isolated and not completely isolated, by the virtual machine from the hardware and virtualization layer.
Examples of paravirtualization include Xen and VMware.
Operating System Virtualization or Virtualization at the OS level
In Operating System Virtualization, a user installs the virtualization software in the operating system(OS) of his system similar to any other application and uses this application to generate and operate several virtual machines.
In this type of Virtualization, the virtualization software directly allows access to all of the created virtual machines to the user. Operating system virtualization may affect compatibility issues of hardware even when the hardware driver is not allocated to the virtualization software as the host OS provides hardware devices with the mandatory support,
Advantages of Server Virtualization
Virtualization improves the efficiency of the cloud which makes optimization of several complex systems easier. Because of this, organizations have the performance and optimization to be able to access data that was either unavailable or very hard to collect previously.
With a lesser number of servers, the amount of racks and cables in the data center is drastically reduced. This makes deployments and troubleshooting easier. The organization can achieve the exact computing goals with just a fraction of the space, power, and cooling wanted for the physical server complement.
As virtualization enables one physical server to do the work of several servers, the total number of servers in the organization can easily be reduced. This is called Server Consolidation. To make it more clear, let’s assume there are currently 10 physical servers, each of which is running a single application. After virtualization, each physical server might host 3 virtual machines, with each virtual machine running an application. Then, the organization would only need 4 physical servers to run the same 10 workloads.
Virtualization centralizes resource control and virtual machine instance creation. Modern virtualization adds a lot of tools and features that give the Information Technology administrators control and see the execution of the virtualized environment.
Drawbacks of Server Virtualization
Running more than one workload on the same physical computer has risks for the organization. With virtualization, a server failure can affect several workloads, potentially causing a greater threat to the organization, its employees, partners, and consumers.
Virtualization tends to assign more memory than the server actually has. This is called memory overcommitment. Overcommitment is undesirable as the additional latency of disk access can slow the virtual machines’ performance. Another bottleneck is network bandwidth as virtual machines on the same server request network access.
A constant challenge with Server Virtualization and virtual machines is the creation and deleting of virtual machines. Virtual machines that are not in use continue to use up valuable server resources but only do a little valuable work. While those resources are not available to other virtual machines. With time, virtual machines increase and the organization runs short of resources, forcing it to do unnecessary and unplanned investments for additional capacity.
In this section, we will discuss some scenarios where Server Virtualization is used.
Server virtualization makes it easier to ensure that the platform can be scaled as required to handle the large volumes and varied data involved in big data analysis. The extent of the variety and volume of structured and unstructured data may not be known before starting the analysis. This uncertainty points toward the need for server virtualization, even more, providing the infrastructure with the capability to meet the required demand for processing very large data sets.
Virtualization reduces the physical server count, allowing an organization to lower the number of physical servers in the data center and run vastly more workloads without adding servers. As mentioned earlier, this is called Server Consolidation. The lesser server count also saves the data center space, power, and cooling, which can even eliminate the need of building new data center facilities. In addition, virtualization platforms routinely provide powerful capabilities such as centralized virtual machine management, virtual machine migration, and workload/data protection.
Frequently Asked Questions
What is a hypervisor?
A hypervisor can be considered as the technology that manages traffic between virtual machines and physical machines. Server virtualization employs the hypervisor to efficiently use the physical resources.
Give a comparison between Full Virtualization and Server Virtualization?
Which organization took the first major steps towards Virtualization.
IBM started with the first virtualization of system memory in 1960s.
Conclusion
This article extensively discusses Server Virtualization, its properties, advantages, drawbacks, and applications.
We hope that this blog has helped you enhance your knowledge regarding Server Virtualization, and if you would like to learn more, check out our articles on Coding Ninjas Blogs. You can refer to our Interview Experiences, Problems, and Guided Paths to strengthen your placement preparation.
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