What is Server Virtualization?

Virtual Private Servers (VPS), the term virtualization has created a lot of buzzes. However, at the same time, it is still not very clear what it really is and what it entails. In this blog post, I’ll be covering the basics of What Server Virtualization is, its types and the Pros and Cons for the same, to help you leverage the best of it.

Before we move on to Server Virtualization, let’s have a look at what Virtualization in general means.

Virtualization refers to the act of creating a virtual version of something, including virtual computer hardware platforms, storage devices, and computer network resources. In simple words, it refers to running more than one Operating System on a single physical hardware. An easy example to understand this is, partitioning a single hard drive into two hard drives. This way there are ‘virtually’ two hard drives but in reality, there is only one.

What is Server Virtualization

Server Virtualization as the name suggests involves ‘servers’. In this a physical server is partitioned into several smaller virtual servers, enabling the server to utilize its resources to the maximum. Here, the server resources are isolated (hidden) from other users in the virtual environment. These virtual environments are known as Virtual Private Servers/Virtual Machines, that in turn act as exclusive physical devices. The software used to partition the server is known as a Hypervisor.

Why use Server Virtualization

Virtualization is an ideal solution for small to mid resource usage applications. Some of the reasons to use server virtualization are:

  1. Virtualization helps in preserving space, as several resources share the same physical space owing to the partition. This also helps in effective resource management.
  2. Virtual Servers offer users the privilege of the dedicated server but at a less price. This is helpful in case of small and medium-sized businesses that do not require the whole dedicated infrastructure and resources.
  3. Backing up of data is simple thereby preventing data loss.

Although there are several reasons to choose Server Virtualization, choosing the right technology too is equally important. There are two widely used types namely, KVM (Kernel-based Virtual Machine) and Virtuozzo.

KVM stands for Kernel-based Virtual Machine, it is a Virtual Private Server primarily for Linux OS though it does support Windows, BSD and Solaris OS’s as guests. KVM is virtualization in the true sense as VPS operates as its own server, not dependent on the host node. It is open source and hardware-based virtualization.

Virtuozzo, on the other hand, is not a free and open source software program. Virtuozzo is container-based and comes with a proprietary Kernel Service Abstraction Layer (KSAL) that manages access to the kernel and prevents any single VPS from bringing the entire physical server down. Also, it addresses virtualization by running a single OS kernel as its core.

Pros and Cons of KVM and Virtuozzo

Even though both KVM and Virtuozzo are popular virtualization software, each has its set of Pros and Cons that end up being the deciding factor. Here is a list of the Pros and Cons of each:

Pros of KVM:

  1. Being open source, KVM is priced relatively lower.
  2. As the base of KVM is Linux, the security is enhanced.

Cons of KVM:

  1. One of the major disadvantages of using KVM is the complexity of the setup and it requires adequate networking knowledge.
  2. KVM virtualization is available only to certain limited processes and lacks manageability features.

Pros of Virtuozzo:

  1. Server resources are utilized efficiently.
  2. Has a web-based GUI Panel. Also, it is an independent platform and, can be used with both Linux and Windows.

Cons of Virtuozzo:

  1. As RAM is shared, there is always a shortage of RAM. This may lead to the killing of a process to compensate the lack of RAM.
  2. Sharing of resources isn’t that great.


Server Virtualization is growing and will continue to grow with the advances in technology. If you want full control over your server, then KVM should be your choice. On the other hand, if you have no major requirements, then Virtuozzo is far more affordable than KVM. Eventually what you as a user choose to invest on is personally your choice depending on your usage.

If you have any more points based on your experience, we would love to hear them in the comments below.

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