Virtualization is a method of providing computing power that is abstracted from the hardware implementation, and provides isolation of physical server platform processes from each other.
Types of Virtualization
The technology can be classified into 5 application areas:
- Platform. Creating a full virtual copy of the platform that emulates physical hardware.
- Operating systems. Emulation of several guest operating systems on a single one. There are different variants of this option. Below we will consider it in more detail.
- RAM. Consolidation of RAM from different sources into a single virtual array. Another option is to isolate a fixed amount of memory for selected services.
- Storage. Combining hardware disk space into a single virtual pool. Most Category A vendors use this approach, which is called block virtualization. Another virtualization option is distributed storage (DS). The file system is distributed across multiple storage devices and is accessible from any connection point via file protocols.
- Databases. Database virtualization creates unified access to information regardless of its location, type, management system, etc. Users can work directly with the data.
- Network Infrastructure. Consolidation of network resources (software and hardware) into a single network.
- Hardware. The technology is supported by a special software component called a hypervisor. Booting from the hypervisor starts as soon as the server is powered on, without starting the operating system. It also isolates the VMs at the hardware level. A prerequisite is that the processor supports virtualization technology. At Intel it is Intel VT, at the vendor AMD it is AMD-V.
- Software. The implementation takes place inside the operating system with special software. In this case, the server operating system is loaded first, and then the VMs are started. Isolation of virtual machines takes place at OS level.
- Containerized. Works at the operating system level and only with special software units – containers. They contain all necessary libraries, which are isolated from each other by the software hypervisor.
Area of application
Virtualization is used for different purposes, let’s list the main ones:
- Increasing the efficiency of server equipment. If a company uses one physical server, which has a load of 20-30%, several virtual servers can be added to it with the help of technology. As a result, the organization receives a significant reduction in financial costs, since the purchase of several physical servers will be much more expensive than virtualization licenses.
- Using virtual operating systems, administrators create isolated spaces to test new software products. A snapshot option is also available for them, ensuring instant OS recovery in case of a critical system error or crash.
- Virtual desktops (VDI) have become an integral part of many companies because of the coronavirus epidemic. The user is given access to a remote desktop that is accessible for interaction from any computer.
- The quick snapshots option of virtual machines is also used to back up working virtual hardware and applications. The snapshot is created in seconds, and the return to the initial state is also done in a short period of time. In this way, the company can ensure high availability and fault-tolerance of critical infrastructure nodes.
- Virtualization for storage provides high reliability and speed by partitioning the disk space into small blocks. Rebuild times in case of disk failures are also much shorter than in the classic model.