XenServer, like many other bare-metal hypervisors, only supports a small bunch of RAID controllers. The difference between it and for example VMware ESXi is that XenServer is pretty much a CentOS minimal install with some proprietary administration tools and a pretty decent remote manager (only for Windows as long as I know…) while ESXi is a completely proprietary closed source blob. XenServer being based on CentOS makes it possible to do many weird unsupported things, like installing it on a software fake RAID on ICH8R. …