I know that using VMWare ESX, you recommend usinf File I/O. But I would like to know using XenServer and VirtualIron what would you recommend?

I'm also wondering on Xenserver 4.1, would it be appropriate to use a HBA such as the QLogic Q4060C on th host, should I use one in my DSS storage server too? Would that influence also block I/O vs File I/O

Thank you