Thin Disk – Is it really thin?


Just during a test a scenario I face something interesting which I thought it would be good to share it here.

So, from now on – I’ll share my personal work on VMware vSphere here (this time it wouldn’t be like my Exams notes ;))

OK, let start.

As all of you know we have two king of virtual disk in the VMware vSphere, Yes, Thin-disk and Thick-disk.

As all of us know, the thick-disks size would be as the size we want, and it will get the space as soon as we press the button of Finish or Create.

In the other hand, we have the thin-disk which shouldn’t be like this. so it means, it must get the space as we start using it.

We all know it.

When you check it in the datastore browser, you will see this two image for think and thick disk.







But what is the status of disk-flat.vmdk for these two disk (you can check it via console or by using ssh)? can you guess?

First Thick-disk


And now, the Thin-disk


Is the last photo is what you expected to see? Why should VMware show us the actual usage in datastore browser but show something else in console?

by the way, check the size

thin and thick have the same size, 40GB which shown as 42949672960, by dividing this number to 40, you will have “1,073,741,824


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  1. Use “du” command to see the exact usage of the VMDK OR VI Client Datastore Browser and select the particular VMDK file. It is REALLY THIN.. 🙂

    du -kh Thin-VM-flad.vmdk

  2. That’s a good article about Thin Disk – Is it really thin? – Kasraeian. Thanks for the info.

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