ESDS Knowledge Base


Frequently Asked Questions About Virtualization

The term “virtualization” is used frequently, but especially in relation to the servers. Here are answers to some frequently asked questions.

What Is Server Virtualization?

Virtualization is a term often applied to a wide range of technologies. In essence, virtualization technology means the use of distributed software hardware. In the area of server virtualization,  it means that some servers (Windows, Linux, etc.) can be placed on the same physical hardware. Thus, the two Linux-and Windows-based servers running on three machines can be virtualized and made to work on one server.

What Is A Virtual Machine?

Virtual Machine: The term is used for server environments running on the same hardware. Thus, in the example above, the division of Linux and Windows-based servers running on one physical server, is due to the virtual machine – special software that separates the hardware resources.

How Does Virtualization Works?

Typically, server virtualization separates the physical server resources. The physical disk is divided into parts that use different virtual servers. Computing resources are treated as the primary server resource pool, which can then be shared between virtual machines. Except for the sharing of computing resources, each virtual server acts as a single machine, the problems associated with operating software on one server does not affect other virtual machines on the same physical server.

What Are The Benefits Of Virtualization?

Benefits of properly designed and implemented virtualization are enormous.

Server Consolidation: The most frequently voiced advantage of virtualization. If applications running on different computers do not use all the computing resources of their computers, they can be combined onto fewer servers through virtualization technology. Usually used on physical servers that only uses 20 percent of computing power, and using virtualization server environments, you can improve hardware utilization upto 60 – 80 percent. Consolidation ratio is obtained by 3:1 or 4:1.

Minimization of the occupied space: Server virtualization reduces the number of physical servers that the company should use. This means that you can use a smaller data center, and, consequently, reduce the cost of cooling and electricity.

Decrease in value of equipment: Since virtualization allows for more efficient use of available resources, require fewer physical servers, resulting in savings of money spent on equipment and its contents.

Flexibility and speed: Because virtualization allows you to quickly create a variety of operating environments, it becomes easy to launch new version of the application to carry out transfer applications in the new environment, as well as to restore the system after the collapse.

Easy testing and development: Virtualization accelerates the development and testing, as easy deployment across operating systems. Virtualization allows developers to compare the performance of applications in various operating environments, and test applications in virtual environments (thus avoiding the destabilization of “working” system, which users can use during the test).

Which Issues Should Be Taken Seriously?

Cost of software / Licensing : One of the biggest problems, which must not be forgotten. Virtualization allows you to easily create new servers, and each of these server environments require a separate license for the software. If you are using the open-source, it will not be a problem, but if you run a paid environment, their deployment could lead to higher license fees.

The effectiveness of planning: In order to realize the full benefits of virtualization, it is important to match the hardware capabilities of the server with their requirements. In practice, this amounts to setting the maximum number of virtual servers on a physical server without degrading the performance of these servers.

Education: As with any change, the introduction of virtualization in the IT-environment will require training. Must take the costs (both time and money) into account.

Management: Despite the fact that the use of virtual servers reduces the amount of physical hardware, virtual machines require management.

High expectations from consolidation: Consolidation ratio depends on two things: the power of the current physical servers and resource requirements of existing applications. If existing servers have sufficient capacity, and your applications use them rationally, we can expect a high rate of consolidation. Conversely, if your server is not as powerful, but your applications use so much of the resources, do not expect the high rate of consolidation.

The increasing amount of investment: This is a potential problem. To realize the full benefits of virtualization, virtual machines must be located on a server with powerful processors. Less powerful hardware reduces the benefits of virtualization. There should be a compromise between the cost of new equipment and reduce the funding of the less powerful computers.

Unavailability of some systems: Especially in areas such as security, some systems are still not adapted to the peculiarities of virtualization. Many firewalls, for example, continue to believe that an IP-address corresponds to a single unit.

What Is The Difference Between Migration From Physical Server Hosting To Virtual?

Not such a big difference. Despite the fact that there are differences between operating systems, etc., the migration of a physical server into virtual entails the same consequences as the migration from one physical server to another.

What operating systems run on virtual servers?

It depends on the individual virtualization solutions, but almost all of the virtual systems work with Windows, Unix and Linux operating systems.

What Virtualization Tools Are Most Common?

So far dominated by VMware and controls 55 percent of virtual servers. Next comes the IBM (9,8 percent of the market). In the back of them breathes Microsoft, and it is quite possible that soon overtake due to the growing popularity of Hyper-V. Among other market participants, it should be noted SWsoft and Xen, respectively, with 6 and 3 percent of the market. Data, IDC.

How Many Virtual Machines Can One Server Run?

Number of virtual machines that can be deployed on the server, depending on server capacity (memory, processor speed, etc.) and application resource requirements for the virtual server. The higher capacity equipment and lower their consumption, the greater the number of virtual machines can be placed.

Conversely, a small capacity and high consumption of resources means that a smaller number of virtual machines can be placed on a single physical server.

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