how can reclaim datastore space (decrease from virtual disk space and increase to datastore)

dear all


i have a question about disk space this is my senario:

i have acreated a virtual machine with 50G HDD now i have increase my vm disk space to 100G from vm edit setting now i want decrease disk space from 100 to 50G my main question is now when decrease disk from 100G to 50G how can add this 50G free space to main datastore on esxi or how can reclaim ?



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2 Replies

Hi baber,

Please take a look at this thread: Possible to take back the disk space that was mistakenly allocated?

Basically there is no "easy" way to shrink the VMDK and recover the space - you need to either truncate the existing disk, use VMware converter or add another data disk and migrate data.

Hope this helps.

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VMware Employee
VMware Employee


Good day.

I'm afraid to say but there is no way that you can decrease the provisioned vmdk from the VM -> Edit settings as the ESXi hypervisor is not aware of the file system layout and cannot ensure a safe shrink operation

The only supported way to achieve this is my making use of VMware Standalone converter.


- Before you convert VM, please use de-fragment tool within the guest OS to defrag the file system and then shrink the partition residing within a disk/vmdk before reducing the size of a virtual disk.

- Once this is achieved, install the Vmware Standlone converter on VM or any remote machine and convert the VM/disks. During the process you do have an option to increase or decrease the hard disks.

- Also if the VM has multiple hard disks/vmdks and if you wish not to convert all the VMDK's/un-necessary vmdks, you may choose to un-check them during this process too.

- Once the VM is converted, you can simply attach the VMDK's which were removed earlier to this new converted VM from the Edit settings.

( Make sure you convert OS drive/VMDK along with the vmdk in question during the conversion )

VMware Training - Physical to Virtual (P2V) Migrations with the VMware vCenter Converter - YouTube

I hope this solves your problem.


Pradeep Venkatesh

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