Linked Clone Ad hoc space reclamation from allocated unused disk space

Horizon View 5.2 leverages a new vSphere capability that implements a new disk format for VMs on VMFS that allow for grain reduction size & more efficiently utilization of allocated blocks by filling it with real data. Unused space is reclaimed and Linked Clone desktops stay small.

These are blocks that were previously written but currently are unaddressed in a file system/database due to file deletions, temporary files, and so on.  There are two steps involved in the space reclamation feature: The first step is the wipe operation that frees up a contiguous area of free space in the virtual machine disk (VMDK); the second step is the shrink, which unmaps or truncates that area of free space to enable the physical storage to be returned to the free pool. For a deep-dive on the technology read Space-Efficient Sparse Virtual Disks and VMware View.


Wipe and shrink operations are managed by Horizon View according to the policies set up by the administrator. This is the best way to reclaim space, but you can also force a manual/ad hoc space reclamation operation by running the following command on the View Connection Server:


vdmadmin -M -d -m -markForSpaceReclamation


*Refer the View 5.2 Administration guide for more information about using this command.


This article was first published by Andre Leibovici (@andreleibovici) at

1 comment

    • Miro on 07/22/2013 at 9:38 am


    Thanks for your Information at first, then I’m wondering that are there any other options excepted the disk descriptor be contained in the file “hostname_checkpoint.vmdk” with LC model? and generally speaking, what’s the reason cause size grow of this file? In my environment, some av soft will cause the size of this file grow soooooo fast. in my opinion, it should be found in the “delta.vmdk” if av soft cause any file changed may cause LC operation.


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