Well, ran into an issue where we couldn't create a datastore on our freshly set up array. A lot of people said the solution was to install windows and format the disks with NTFS. While that might work, I didn't want to do that.
You have a couple of other options
You can use a Windows Vista/7/2008/2008r2 install disk and after you click the first install button, press Shift+F10 to get a command prompt. You can then use DiskPart.
Or, if you would rather do this in the ESX shell try zeroing out