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Virtual Machine Disk Format
VMDK File Format icon.png
Filename extension.vmdk
Developed byVMware
Latest release
(December 20, 2011)
Type of formatDisk image file

VMDK (short for Virtual Machine Disk) is a file format that describes containers for virtual hard disk drives to be used in virtual machines like VMware Workstation or VirtualBox.

Initially developed by VMware for its virtual appliance products, VMDK 5.0 is now an open format[1] and is one of the disk formats used inside the Open Virtualization Format for virtual appliances.

The maximum VMDK size is generally 2TB for most applications, but in September 2013, VMware vSphere 5.5 introduced 62TB VMDK capacity.[2]


All VMware virtualization products support VMDK; this includes VMware Workstation, VMware Workstation Player, VMware Server, VMware Fusion, VMware ESX, VMware ESXi, and all software-plus-service offerings that incorporate them.

Third-party software that support VMDK include:

Virtual disk provisioning options[edit]

  • thin: Blocks are not allocated or zeroed during initial provisioning. Block allocation and zeroing is performed at first access.
  • zeroedthick: Blocks are allocated during initial provisioning but are not zeroed until first access.
  • eagerzeroedthick: Blocks are allocated and zeroed during initial provisioning.

See also[edit]


  1. ^ "Virtual Disk Format 5.0" (PDF). VMware. December 20, 2011.
  2. ^ "vSphere 5.5 Storage Enhancements Part 1: 62TB VMDK". CormacHogan.com. 24 September 2013. Retrieved 11 September 2017.
  3. ^ "Parallels Announces Parallels Desktop 10 for Mac". www.parallels.com.
  4. ^ "Chapter 5. Virtual storage". www.virtualbox.org.
  5. ^ "Oracle and Sun Microsystems - Strategic Acquisitions - Oracle" (PDF). www.sun.com.

External links[edit]