Wow that was quick ;-)
I have followed the wiki articale about Intel Modular Server with Multipath (http://pve.proxmox.com/wiki/Intel_Modular_Server#Optional:_Configure_Multi-Path).
root@timo:~# multipath -llvmdisks (2225d0001557dd1ea) dm-1 Intel,Multi-Flex
size=1000G features='1...