In Symantec DLP, all servers and agents are independent in relation to their work once they are configured and all policies are distributed. All servers will continue doing their job, if communications are lost. If DB is down, Enforce will continue processing and storing incidents in a temporary space, and once DB is up, Enforce will catch up with incidents writing. If enforce servers fills up HD space, it will stop processing and detector servers will stop sending incidents and store them locally; something for agents when they are off the network or cannot talk to Endpoint server.
Good luck with your DLP and I will recommend having a test environment so you can test scenarios like this one.