Description here...
```bash
# Docs
http://wiki.debian.org/Xen?highlight=((DebianInstaller|Xen))#DomU.28guest.29
# 20 Gb disk image
dd if=/dev/zero of=/srv/xen/mailserver.img oflag=direct bs=1M seek=20470 count=1
# Copy template
cp template.cfg domu.cfg
# Edit template
xxx
# Start domU
xm create -c domu.cfg
```