VMDK (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 is now an open format and is one of the disk formats used in 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.
Products that use the VMDK format as the native file format include
Third-party products with VMDK support include
Virtual Disk Provisioning Options
- 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.