CentOS - Jul 2013 - Best practices to setup XEN running on CentOS 6.4

Hi everyone,

I'm looking for advice on the best way to setup the guest disks on a 
single-server XEN system running on a Centos 6.4 fresh minimal install 
as the dom0.

I currently have a system running a traditional VHD disk image for each 
guest but I'm having disk I/O difficulties and I am looking to optimize 
it the best way I can.  The host disks are two classic 500GB SATA-III 
drives running in software RAID.

My question is what is the best way to set this type of system up? Using 
the VHD disks or a dedicated LVM partition?

Ideally the host will run a few VM's, development, MySQL/Memcached, and 
Web Server utilities.

My current planned disk layout is to have a host system running a raid'd 
root 20GB partition, leaving the rest for VM's. Should the remaining 
block be a complete LVM device and carve that up for VM's, or is there a 
better "accepted practice" for a setup like this?

Thanks