The UVS license allows you to enable the number of nodes that the UVS manager can manage. 


For example, if you would like to deploy a cluster with 3 Mars 400, you need a license for 24 nodes for using the UVS. 


If you want to expand your Ceph cluster with more Mars 400, you have to request a new license with more nodes enabled from Ambedded. Otherwise, the UVS manager will show an error when you add new OSDs. 


UVS license has an expire duration of 10 years.


You can refer to this article "How to update UVS license when adding more Mars 400?"