How to thin provision an exsiting VMWare disk on ESXi without virtual center

abx21 — Fri, 03 Oct 2008 14:51:39 +0000

If you are like me then after you installed ESXi you went and created a ton of virtual hosts, then realized that you were short on disk space. In doing research on using NFS as a datastore, I read how by default images on NFS were thin provisioned. In a bit of a jealous moment, I wondered why I didn’t have that option. I learned that by using the RCLI appliance it is possible to convert. “Vmkfstools -i” is your friend. First you must shutdown your VM, in this case called “test-vm”. Then from the RCLI run the vmkfstools command as follows:


vmkfstools -i /vmfs/volumes/datastore1/test-vm/test-vm.vmdk /vmfs/volumes/datastore1/test-vm/testvm-thin.vmdk -d 'thin' -a lsilogic

The command prompt on the RCLI appliance will not return until the copy/conversion is done, but you can see the progress graphically in the tasks windows on your VI client. Once the copy is done, go into the settings of your VM, delete the hard disk, and add a new hard disk pointing to the “thin” vmdk you created. Boot your vm, if it all works then you can use the datastore browser to delete the thick vmdk and you are done.

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How to thin provision an exsiting VMWare disk on ESXi without virtual center