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Virtual Machine Disk Format
VMDK File Format icon.png
Filename extension .vmdk
Developed by VMware
Type of format Disk image file
Website www.vmware.com/interfaces/vmdk.html

VMDK (Virtual Machine Disk) is a file format developed by VMware for its virtual appliance products, but is now an open format.[1] The format is a container for virtual hard disk drives to be used in virtual machines like VMware Workstation or VirtualBox. The maximum VMDK size is generally 2TB for most applications, but in September, 2013, VMware vSphere 5.5 introduced 62TB VMDK capacity.


Products that use the VMDK format as the native file format include:

Third-party products with VMDK support include:

  • Sun xVM: natively supports VMDK format[2]
  • QEMU: natively supports VMDK format and provides the qemu-img utility to convert VMDK images to a number of different formats
  • VirtualBox (part of the Oracle VM suite) also supports VMDK files[3]
  • SUSE Studio: builds virtual appliances using the VMDK format, among others
  • Norton GHOST: Hard drive imaging software

Software libraries with VMDK support 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]


External links[edit]