To revert to the method used in 5.0 and earlier of not creating a local VMFS partition add the the parameter
--novmfsondisk to the install configuration line in the kickstart (
ks.cfg) script in ESXi 5.1 and newer.
Example:
install --firstdisk –preservevmfs --novmfsondisk
This will preserve a VMFS filesystem if one is already present on the disk but will not create a VMFS filesystems if one is not already present on disk.