Upgrading VMFS3 Volumes to VMFS5
vSphere 5.0 supports VMFS5 volumes, which have improved scalability and performance. You can upgrade from VMFS3 to VMFS5 by using the vSphere Client, the vmkfstools ESXi Shell command, or the esxcli storage vmfs upgrade command. Pass the volume label or the volume UUID to the ESXCLI command.
Important You cannot upgrade VMFS3 volumes to VMFS5 with the vmkfstools command included in vSphere CLI.