On Sat, 4 Nov 2006, Geert Hendrickx wrote:

> The third (and I think most-used) option is to run the software RAID in the
> dom0 and provide each domU with a block device on the RAID (e.g. raid0g).
> The only challenge then (as well is with option two) is to teach GRUB, but
> this has been discussed on this list before.

You only need to teach grub about your boot disks;  I use a compact flash 
card as my boot disk-  it's on a cf->IDE adaptor so nothing special for 
grub. After the system boots, it brings up the raid for the DomUs.