VMware: How to Shrink a Thin VMDK on ESXi 5.0

Many customer/service request we receive from our client is..

is it possible to reduce the disk?

This means the files inside the VM, but the size of the VMDK as well.  

So I wanted to shrink my VMDK size as much as possible.  After cleaning up the VM itself and running sdelete, it’s time to shrink the VMDK.

First let’s review the actual usage of it:

The virtual disk size can be seen with ls –lh *.vmdk.  In my example, I have a 40 GB virtual size.

To see the ‘real’ size of the vmdk, run du –h *.vmdk.  This gives us a 36 GB size (while the VM itself actually uses about 10 GB).

Issue the command vmkfstools –punchzero VM.vmdk.  This will take a while so be patient (and oh yes, you VM must be powered off).

On a 40 GB VMDK it took me about 10 minutes, but this will depend mostly on your SAN speed.

After it’s done, let’s re-issue du –h *.vmdk.

Nice, now it’s actually 10.8 GB.