Best way to delete a large amount of data

Best way to delete a large amount of data

del /f/s/q > foldername > nul

rmdir /s /q foldername

Once that's complete...

sdelete -z <drive letter> 

Version 1.6 of sysinternals sdelete option z is used to zero out the drive which can be used for VMware conversion of thick provisioned disks to thin provisioned disks.