Read the documentation http://www.erlang.org/doc/apps/mnesia/Mnesia_chap5.html#id76406 Disc-less Nodes section talks about how to implement this use case. Below steps setup such environment.
1. Start mNode
erl -sname m_node -mnesia dir "/tmp/funky/"
2.Start Service node
erl -sname s1
3. Create Cluster
net_adm:ping('s1@_)').
4. On m_node run
mnesia:change_config(extra_db_nodes, ['s1@_']).
mnesia:create_table(funky, []).
5. On s1 node
mnesia:start().
mneisa:info().
remote = [funky] // Points to Remote table funky on node m_node
ram_copies = [schema] // Ram copy of schema is kept in each service node.