3. Synchronization for pull replication is less disruptive and occurs only when needed by each site, not when a central master site thinks it is best to update.
7. An increasingly popular option for data distribution as well as for fault tolerance of any database is to store a separate copy of the database at each of two or more sites.
8. Asynchronous technology can result in unsatisfactorily slow response time because the distributed DBMS is spending considerable time checking that an update is accurately and completely propagated across the network.