What is Virtual Hard Disk? (original) (raw)

Last Updated : 23 Jul, 2025

A virtual hard disk (VHD) works like a normal hard drive but is designed specifically for use in a virtual machine (VM). Virtual Hard Disk is used in virtualization. Virtualization refers to a process of creating a virtual representation of a device or resource, such as a server, storage device, network, as well as an operating system. In this article, we will discuss every point about Virtual Hard Disk.

What is a Virtual Hard Disk (VHD)?

A virtual hard disk (VHD) is a type of disk drive that works same as a normal hard drive. Primary, it is designed for use in a Virtual Machine, this VHD is managed, accessed, and installed in a virtual machine. Virtual hard disk (VHD) often contains the same hard drive sectors found on a physical hard drive, such as disk partitions and a file system. As if, the VHD is portable and accessible from anywhere, so, the data stored in the Disk can be moved with a USB flash memory device.

Types of Virtual Hard Disk

**1. Fixed Hard Disk

The Fixed Hard Disk consumes a fixed amount of space on the host machine's hard disk drive. t contains a RAW disk image followed by a VHD footer (512 bytes). It automatically occupies physical HDD space in the host machine's file system. Fixed VHDs support fast processing speed and constant partitioning

**2. Dynamic virtual hard disk

Dynamic virtual hard disk has a different disk size. Storage space starts at a fixed minimum size and grows as data is added to the VHD. It is just a regular hard disk. Its main advantage is that it speeds up storage space allocation. It takes minimal space usage for VM-level backups.

Benefits of using a Virtual Hard Disk

• **Simplified Backup and Recovery: VHDs allows for quick backups and fast recovery in case of failure.
• **Cost-effectiveness: By allowing multiple virtual machines to run on a single physical machine, VHDs eliminate the need for multiple hardware components, reducing storage and deployment costs.
• **Resource Optimization: Dynamically expanding VHDs help optimize storage utilization, leading to cost-effective storage solutions.
• **Easy installation: VHD files contain pre-built and standard configuration provisions to work in a VHD-specific operating system environment, which simplifies deployment.
• **Isolation and Security: VHDs can be used to create isolated environments for testing and development, reducing the risk of affecting the production environment.
• **Fast replication: Tasks or files from one system can be replicated to another system. This is especially useful for collaborating developers.

Similarities and Differences between Virtual Hard Disk and Physical Hard Disk

• A virtual hard disk has similar functionality to a physical hard disk drive. For example, it often contains the same hard drive sector, such as a file system, disk partition, etc. It appears and acts like a hard disk physically attached to the system. Like a hard disk, a VHD can do the following: Creating Files, Folders, and Disk Sectors, and run OS, and Applications.
• Basically, a VHD is distinguished from a physical hard disk in that it is designed for use by virtual machines and installed in virtual machine infrastructure, typically VMware workstations and Hypervisor VMs. Although a VHD is created on a physical hard drive, it is a "virtualized" file and has its own logical distribution. Its disk size can be fixed or flexible. This site is managed by the operating system (OS) or virtualization manager.

**Steps to Create a Virtual Hard Disk on Windows

Creating a virtual hard disk (VHD) in Windows is a simple process. Windows includes built-in tools for creating and managing VHDs. Here are the steps to create a VHD using the Disk Management tool:

• Open Disk Management (Win + X -> Disk Management).
• Create VHD (Action -> Create VHD).
• Specify location, size, and format.
• Choose disk type (Fixed or Dynamically expanding).
• Initialize Disk (MBR or GPT).
• Create New Volume (follow the wizard).
• Access VHD in File Explorer.

Is VHD and VHDX the same?

A virtual hard disk is saved with the VHD or VHDX file extension. The VHD file format was originally introduced with Connectix Virtual PC and was eventually adopted by Microsoft Hypervisor. It works with many versions of Microsoft's Windows OS. On the other hand, the VHDX is the new file extension used by Microsoft Virtual PC and Virtual Server. VHD is supported by Windows 7 and earlier versions. On the other hand, VHDX is supported by Windows 8 and Windows 10 operating systems, and new version 11. VHDX has new capabilities such as performance improvements, data corruption prevention measures, and a 16TB maximum allowed size. Although the new VHDX file has data corruption prevention measures, it is not completely immune to corruption. Sometimes corruption can occur and cause inaccessibility.