Xenserver VMs start at boot
By default, VMs are not set to start after a server reboot in XenServer 6. In previous versions, there was a check box in XenCenter, but that has been removed.
You can set all VMs to start on boot of the xenserver host with the following command:
for i in `xe vm-list live=true params=uuid|awk NF|cut -d”:” -f 2`;do xe vm-param-get uuid=$i param-name=other-config;done