“A Virtual Machine is nothing but the software generated computing environment to install and run an operating system and supported applications.”
As per the meaning of the word virtual, something that is not real or unrealistic, the term virtual machine (i.e. computer) refers to emulation of a computing environment that runs similar to a physical network, but is reliant on a host computer for hardware resources, viz. hard disk drive, Processor, RAM and more. The host computer is the computer that provides all these resources to the guest (i.e. virtual) machine.
Well, you apparently sound confused enough. Aren’t you? You must have heard the name VMWare – the virtualization software, which enables you to run multiple operating systems on a single computer. Wait! VMWare does not end up with this only. With this and a few like tools, you not only can install multiple operating systems on a computer, but you can also run all of them at the same time.
The prime resource for creating and running virtual machines is the virtualization layer that operates on an operating system that can be either a client or a server. The most amazing fact about virtual machines is that the operating system and installed applications do not know if they are running in an unrealistic environment. Moreover, the entire data including the boot system is stored in a single file (*.vmdk), and requires immense care to keep running seamlessly.
The term VMDK refers to Virtual Machine Disk, which is the extension of data files created by a virtualization software, namely VMWare. In fact, many organizations today go for virtualization (using VMWare or some other virtualization software, viz. VirtualBox, or Virtual PC) to build virtual servers to streamline the overall data storage as well as its usage. However, the overall setup requires pretty safe virtual environment for seamless operations. Corruption in the VMDK (i.e. *.vmdk file extension is specific for VMWare, and is different from other such software) file causes virtual machine failure, which at the corporate level causes a huge data loss. Luckily, virtual data recovery software are available to help you to recover data lost on a virtual machine. Mentioned below are some factors causing corruption in virtual machines and servers:
RAID Corruption or Failure
Some hard drives are combined to build a redundant array of independent disks, usually termed a RAID. Well, RAID devices are used most specifically in organizations (usually RAID 5 or RAID 6 devices) to store and manage a huge amount of data. Since even a RAID is nothing but a collection of hard drives that may fail anytime, causing data loss that is never acceptable. Since RAID 5 and RAID 6 are large RAID devices that contain some hard drives, failure of one of them does not make a big difference. However, failing multiple ones concurrently leads to failure of the RAID and hence, causes loss of huge amount of data.
Corruption in VMDK
A VMDK (*.vmdk) file is an a virtual machine (or server) data file that is specific to VMWare – the virtualization software. In fact, the overall data of a virtual machine setup is saved in a data file that is of VMDK format, and it is located on the host computer. You need to make sure that the VMDK file is secure enough, as it is prone to corruption due to virus or malware infections, power surges, improper or forced system shutdown, bad sectors, and more. Also, a corrupt VMDK file can never be used to run a virtual machine setup.
System Hardware Issues
As mentioned earlier, a virtual machine involves a host and a guest computer, both of them can be run at the same time in a virtual computing environment using a virtualization software, such as VMWare. However, since virtual (i.e. guest) computer is not aware of any virtual setup, both host and guest computers run on a common hardware setup. In case the host computer meets a hardware malfunctioning issue, the host computer also fails to boot. In fact, the entire virtual machine setup fails, thereby causing data loss.
Corruption in VMFS File System on ESX Server
VMFS (Virtual Machine File System) is a VMWare specific high-performance file system that is used for virtual machines. VMFS facilitates multiple host computers to read and write access shared storage at the same time. Using this file system, provisioning and administration of virtual machines are quite simple, as the entire virtual machine state is stored at a central location. Besides, by creating a point-in-time copy of data stored on a virtual machine, it facilitates performing a backup, testing, and recovery operations. However, in case this file system gets corrupt, virtual machine data is like all gone.
Deleting VMFS Files Unintentionally
Virtual Machine File System is quite advanced, and it played multiple major roles in both establishments and intended working of virtual machines created with a virtualization software, namely VMWare. VMFS files store crucial data that is quite essential to run a virtual machine seamlessly. In case you delete such a file unintentionally, you no longer be able to access your data stored on a virtual server. Alternatively, you lose all your data.
Since individual users do not preferably go for virtualization unless they aim for some professional work, it is quite an unusual situation that demands rectification at the earliest. On the other hand, it is quite common in software and many other industries.