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All about Virtual Machine Compatibility

By CIOReview | Thursday, September 14, 2017

Virtual machines technology refers to the concept of virtualizing an entire machine, avoiding the constraints of a real machine and the constraints of the hardware resources to make possible a higher degree of software flexibility and portability. In the present scenario, virtual machines are increasingly becoming a vital part of the computer system design. Virtual machines provide cross-platform compatibility, system security, reliability, flexibility, and resource efficiency. They are designed to solve difficulties in using and combining major computer system components, it plays a key role in many disciplines, including programming languages, computer architecture, and operating systems.

A virtual computer system is referred to as VW or virtual machine, which is, in simpler words a software container that is tightly isolated, with an operating system and application inside. Each self-contained VM is completely independent and numerous virtual machines on a single computer system make it possible for multiple operating systems and applications to run on a single physical server, which is also called as the host. Additionally, software termed as hypervisor helps to separate or decouple the virtual machines from the physical system and dynamically assigns computing resources to each individual virtual machine as required.

For example, the hypervisor helps virtual machines to run Windows Server and Linux operating systems on a single physical system. This helps in decreasing the use of numerous hardware systems, streaming it down to a lesser number of systems with more efficiency. When virtual machines are created in a particular hypervisor platform, it will be difficult to use in a different hypervisor environment. Most often, virtualization file formats are highly incompatible and to achieve compatibility across multiple hypervisors there are certain criteria to be considered.

Having a working knowledge of virtualization file and disk format is essential when it comes to virtual machine compatibility across multiple hypervisor environments. Two different files to the least, are required to store a virtual machine, which is a hard disk file that is implemented to store all the files that are used within the virtual machine and a second file that describes the virtual machine itself. While transforming a virtual machine from a particular hypervisor to a different hypervisor, it should be made sure that both the files are adaptable to the target hypervisor. It is also important to make sure that the source disk formats are usable on the target hypervisor platform. There are a numerous number of disk format types with multiple features that enhance the hypervisor program. This might lead to the difficult compatibility with the hypervisor. The common disk format includes virtual machine disk (VMDK), RAW, virtual hard disk (VHD) and Qcow2.

In addition to the multiple disk formats, there are virtual machine specification file formats. These file formats comprise of XML files which are used in a KVM environment, VMX file format which referrers to virtual machines are used in a VMware environment. When it comes to compatibility, these file formats are not as important as the virtual disk formats . When the virtual machine description file is unable to be read, it is quite easy to recreate the virtual machine on the target platform.