It acts as an intermediate floor between computer hardware and system software running on it. The idea of server virtualization technology is on a single physical machine can form multiple independent virtual machines.
I. The concept of server virtualization.
Virtualization allows to create multiple virtual machines on one physical server, each virtual machine also allocated hardware resources such as CPU, Ram, including the real network cards, hard drives, other resources, and the operating system. When running the application, the user will not realize that applications running on virtual hardware layer.
The processor of large computer systems designed to support virtualization technology and allows the transfer of the command or the sensitive process of virtual machines can influence directly to system resources for the server processing, then virtualization layer will simulate results to return to the virtual machine. However, not all matches are processors that support virtualization. The old processor on the desktop does not support this functionality. Today the two major processor manufacturers in the world are Intel and AMD are trying to integrate virtualization technology into their products. The processor has virtualization is typically Intel VT (Virtual Technology) or AMD Pacifica.
Use of virtualization technology has brought to users the Add-ons. Being able to run multiple operating systems simultaneously on the same computer for research and study reviews a product or operating system a software utility. But don't stop there, the possibilities and benefits of virtualization is also more than that and where to reap success and created the brand of virtualization technology that is an application server systems and network systems.
Server virtualization is really not of interest for the Temple in recent years. Due to the many problems of the technology and the user hasn't really interested in benefits as well as the lack of a knowledgeable team about this technology should be applying it to the heating system the system is very dè places. But when faced with the reality of the crisis the global economy then any agency, organization, enterprises would also need attention in order to find a solution to save more. It is also found at virtualization technology foothold for themselves in the field of information technology in the world.
Now there are many suppliers of server products and software to control the focus of investment in research and development of this technology as HP, IBM, Microsoft, and Vmware. Various forms of virtualization and can be divided into two main forms is virtualization hardware and virtualization software. From the above two types, later to grow into many types of virtualization have different structures and functions as the VMM-Hypervisor, VMM, Hybrid ...
Hardware virtualization is also known as the server. The form of this virtualization allows creating multiple virtual machines on a single physical server. Each virtual machine runs its own operating system that is allocated to the hardware resources such as CPU, hard drive rhythms pulse number and memory ... The server's resources can be dynamically allocated in a flexible manner depending on the needs of each virtual machine. This solution allows the bulky Server system into a single server and the previous server now acts as the virtual machine applications running on it.
Virtualization software, also known as the OS. It actually just copies a copy of a major operating system do a lot of the operating system and enables the application virtual machines can run on it. So, if the host operating system is Linux, then how virtualization will allow more a Linux working on the same machine. This is just a copyright for an operating system and can be used for the virtual machine. The downside of it is not possible to use many different operating systems on the same server.
II. The components of a system virtualization.
1. Physical resources (host machine/hardware host).
The physical resources of the virtualization environment to provide the resources that the virtual machine will use. A large resources environment can be provided for multiple virtual machines running on it and improve the work efficiency of the virtual machine. The physical resources including is the hard drive, ram, network card. ..
2. Virtual software.
This virtualization software layer providing the access for each virtual machine to system resources. It is also responsible for planning and Division of physical resources for the virtual machine. Virtualization software is the Foundation of a virtualization environment. It allows creating virtual machines to users, manages resources and provides the resources to the virtual machine. Beyond virtualization software provides the management interface and the configuration for the virtual machine.
3. Virtual machine.
The term virtual machine is used when describing both the virtual machine (class 3) and virtual operating system (grade 4). The virtual machine is a virtual hardware, an environment or a partition on the drive. In this environment have full hardware devices like a real machine. This is a type of virtualization software based on physical hardware. The guest operating system that we installed on the virtual machine does not know the hardware that it saw as virtual hardware.
4. Guest operating system.
The guest operating system is seen as a software (class 4) is installed on a virtual machine (class 3) help I can use easily and handle issues in the virtualization environment. It helps the user to have the same operation as being on a real physical hardware layer.
When there is enough of the above components, the user can build for themselves an application virtualization system. In addition to the selection of appropriate hardware, users also need to consider using virtualization software or what type of virtualization. This is very important in optimizing performance for the system.
III. Introduction & architecture virtualization levels.
Review on the system architecture, the architecture of virtual server systems can be divided into the following types:
Hypervisor-based (also called bare-metal hypervisor, it is broken down into two categories is Monothic Hypervisor and Microkernel Hypervisor)
In addition, depending on the virtualization products are deployed (such as Vmware, HyperV, Citrix XEN Server) that the level of specific virtualization will be different. The level of virtualization include:
Full virtualization (Full-virtualization): client operating systems (The heating system operating the set on the virtual server) is not changed, and they act like on real hardware.
Parallels virtualization (Paravirtualization): these operating systems will be changed to work better with the hardware. However, this format often has limited support quite a few of the types of client operating systems.
Operating system virtualization.