This article provides steps to reformat the local VMFS partition's block size in ESX 4.x, when there already is an existing ESX installation.
Note: For ESXi servers, reformat the local VMFS3 file system using the VMware vSphere client, or the vmkfstoolscommand. For additional instructions, see:
To reformat the local VMFS partition on your VMware ESX 4.x server after an installation has already been completed:
Prepare the server for booting into the installer CD's live environment: