While trying to write a script to move our VMs to a newly created datastore cluster I discovered a bug in PowerCLI. The issue only comes into play when trying to convert to thin provisioning. I am using PowerCLI 5.1 Release 1 build 793510. If you run this command you get a giant trace stack: Running the same command without the -DiskStorageFormat flag will work fine: Also if you run the command with the thin provision flag against a datastore and not a datastore cluster it works fine as well:

Overview….. Infrastructure Setup You will need three servers besides your basic vSphere setup: TFTP, DHCP and the Auto Deploy server. You will also have to make sure you have PowerCLI Setup. TFTP Server Setup Red Hat/CentOS TFTP Server Setup Download the Deploy-tftp.zip file from vCenter and put it in the TFTP root directory: The file can be found in the web GUI: I put the file in: DHCP Server Setup Just like with TFTP, you can use pretty much anything for DHCP.