Virtualization Knowledge Science Popularization

Virtualization of these three words, nearly two years frequently appear in it websites and magazines, some media also set up a column to report. From last year to now, there has been "the next ten It technology" of the selection, the most widely reported online in Gartner (Gartner consulting Company-the world's most authoritative it research and consulting company) released the "Ten Future It Technology trends," the virtualization technology in the first place.

But the relevant articles on the Internet, more professional, the narrative jerky, and often mixed with other concepts, such as cloud computing, enterprise information, green it, server energy-saving, so that people a puzzled, and add a number of questions. The author transforms it into a popular language to introduce the virtualization technology. Small white, rookie can stop, it and virtualization professionals can bypass.

Concepts and classifications of virtualization

As the name suggests, virtualization is in the calculation of virtual out of some actual computer real things, in order to achieve more convenient, simple, low-cost, high security purposes. For example, virtual computer hardware, you can install the operating system, the existing operating system as a blueprint, and then virtual a few touch the same; virtual an operating system environment, you can install the application software. This explanation, is I very popular statement, strict and precise definition, has not yet seen.

Virtualization technology, after several years of development, has become a huge technical family, its technical form of a wide range of applications to achieve a large basket. But to its classification, the on-line introduction is vague, the classification attribute is different. such as server virtualization, hardware virtualization, CPU virtualization, but in fact they all belong to a category, just according to different attributes of different names.

Now, to get to the next category of virtualization, follow the different attributes:

To achieve hierarchy: hardware virtualization, operating system virtualization, Application Virtualization.

Divided into applied domains: Server virtualization, storage virtualization, network virtualization, desktop virtualization.

There are also derived from a class, can not be categorized, such as CPU virtualization, file virtualization.

These do not attribute the relationship between the category is staggered, the following a brief introduction.

Hardware virtualization of Virtualization classification

Hardware virtualization, which is the most familiar technology for Chinese IT personnel, represents VMware for products that may be used by every programmer. There are a lot of it enthusiasts like me, every day in the tinkering.

Hardware virtualization, is the use of software to virtual a standard computer hardware configuration, such as CPU, memory, hard disk, sound graphics, optical drive, etc., become a virtual bare metal, and then you can install the operating system on it.

Use, first in the operating system to install a hardware virtualization software, with its virtual out of a computer, and then install the system, so that the system running the system, and can be virtual out of multiple computers, install a number of the same or different systems.

Its representative products for VMware, the other several well-known are: Microsoft Virtual PC, open source free VirtualBox.

The hardware resources allocated for virtual machines occupy the resources of the actual hardware, and the performance loss is also greater. Because the virtualization software is installed in the system, again in the virtual computer system, so there is the original system and virtualization software two levels of consumption, in order to improve performance, there is another form of hardware virtualization: Directly on the bare metal to install the virtualization software, and then install multiple systems, and run simultaneously. Skip the original system of this link, performance greatly improved. This virtualization is also called Quasi virtualization. VMware launched the relevant products called VMware ESXi, Microsoft's products are Hyper-V, mainly used in the server area.

Operating system virtualization of virtualization classification

Operating system virtualization is a system for the Matrix, the cloning of multiple systems. It is more flexible than hardware virtualization, because just install a virtualization software in the system, you can take the original system as a sample, quickly cloned the system, the cloned system and the original system to remove some ID identification, the rest are the same.

Like hardware virtualization, it is a virtual multiple operating system, but it is a lot different from hardware virtualization:

1. Operating system virtualization is based on the original system as a sample, virtual a near-touch the same system; Hardware virtualization is the virtual hardware environment, and then the real installation system. They are virtual things different.

2. Operating system virtualization, virtual systems can only be the same system, hardware virtualization, virtual systems can be different systems, such as Linnux, Mac, Windows family.

3. Operating system virtualization, a number of virtual systems have strong links, reflected in: first, multiple virtual systems can be configured at the same time, changed the original system, it changed all; second, if the original system is damaged, all virtual systems will be affected. The virtual system of hardware virtualization is independent of each other and has no connection with the original system. Damage to the original system does not harm the virtual system.

4. Operating system virtualization performance is low, they are virtual systems, rather than hardware virtualization as the real installation of the entity, no hardware virtualization of the virtual hardware layer, also greatly reduce the performance loss.

Virtualization of Application Virtualization for classification

The first two virtualization technologies are mostly applied to enterprises, servers, and some IT professional areas of work. With the development of virtualization technology, gradually from the enterprise to personal, professional to the application of the trend of the development of the Application Virtualization technology, abbreviated application Virtualization. It has recently virtualized upstarts and hot areas.

The first two virtualization purposes are virtual complete real operating system, the purpose of application virtualization is also a virtual operating system, but only to ensure the normal operation of the application of the virtual system of some key parts, such as the registry, C-disk environment, etc., so relatively lightweight, compact.

Play a popular analogy: The system is a table, software is a variety of dishes on the table, the application of virtualization software is a one-time tablecloth. The advantage of laying a tablecloth is that it will not stain the table, even if the tablecloth is dirty, it is easier to take care of it than to clean the table;