I've installed DSS no my XEN server. After reboot it's loosing activated status. What should I do? 

Solution:

Find unique dss.cfg* file of your VM with DSS and add following line to the file:

uuid = '54443858-4E54-2500-904C-0025904C93D8' **

*where dss is name of your VM
**Where  '54443858-4E54-2500-904C-0025904C93D8' should be unique value.