Proxmox VE 2.2 and clvm

[zystem]

In that cases clvm is needed for proxmox 2.2 ?
See wiki
http://pve.proxmox.com/wiki/Proxmox_ISCSI_installation
http://pve.proxmox.com/wiki/Storage_Model
http://pve.proxmox.com/wiki/ISCSI_Multipath
There aro nothing about cLVM.
But pveversion -v output include clvm: 2.02.95-1pve2

So do I need clvm for ISCSI ?
So do I need clvm for Fibre Channel ?
So do I need clvm for GFS2 ?