The implementation and deployment of the Non-Volatile Store (NVS) domain is the responsibility of the user. MC-3020 supplies one or more sample implementations of this domain to serve as design examples and source code "head starts". xtUML.org will develop and collect additional samples over time and make these available to users. However, with the variety of non-volatile storage technologies available and broadly differing platform requirements this deployment is left to the user for the purposes of flexibility.

Class instances and relationship instances (links) are stored in non-volatile storage. Their types are kept distinct from the rest of their instance data. In other words, the NVS domain distinguishes between instance data and link data.

Instances and links will be created and deleted in a rigorous fashion in the action language. Instances will be deleted only after all links have been "unrelated".