XenCenterでVM→Install Xen Server Tools

# mount /dev/xvdd /mnt
# cd /mnt
# cd Linux
# ./install.sh
Detected `CentOS release 6.x (Final)' (centos version 6).

The following changes will be made to this Virtual Machine:
  * update arp_notify sysctl.conf.
  * packages to be installed/upgraded:
    - xe-guest-utilities-6.xxxxx.x86_64.rpm
    - xe-guest-utilities-xenstore-6.xxxxx.x86_64.rpm

Continue? [y/n] y

準備中...                ########################################### [100%]
   1:xe-guest-utilities-xens########################################### [ 50%]
   2:xe-guest-utilities     ########################################### [100%]

You should now reboot this Virtual Machine.
# cd 
# umount /mnt

FreeBSD On XenServerを参照