Thinning vs shrinking

[BobSimon]

VMware ESXi, 6.5.0, 8294253

I want to reclaim unused space from a VM back to the datastore.  I used vSphere Web Client to clone the VM to thin then used Computer Management/Disk Management to shrink the volume with 30GB now unallocated.

The following article on thinning and shrinking left me wondering about differences between these two activities.

Growing, thinning, and shrinking virtual disks for VMware ESX and ESXi (1002019)

1. Can someone explain this?

2. Will vmkfstools -K reduce the size of the .vmdk by 30GB?  If so, will the datastore show up with 30GB more free space in vSphere Client?

[SupreetK]

1) Thinning is converting a disk to thin provision type. This will not release any space.

2) Shrinking is reducing the size of the disk.

3) 'vmkfstools -K' will punch zeroes and reduce the size of the disk.

Please consider marking this answer as "correct" or "helpful" if you think your questions have been answered.

Cheers,

Supreet

[BobSimon]

After shrinking by 30GB, will the datastore show up with that much more free space in vSphere Client?

[SupreetK]

After running 'vmkfstools -K', ideally it should

Please consider marking this answer as "correct" or "helpful" if you think your questions have been answered.

Cheers,

Supreet

[Paul_Knight1]

Are your datastores formatted as VMFS 6?  If so, then 6.5 has automatic UNMAP that releases freed blocks back to the array without manual intervention.  This works best if your backing store is set to thin provisioned.  If your array de-dupes, and you have a thick VM, make sure the free space is zeroed.  Thin provisioning is the most efficient use of disk, but if you have to thick provision a VM, eager-zero will make better use of your array.

[SupreetK]

Lot of caveats with auto-unmap though Made to work with 6.5 U2 onward

Cheers,

Supreet