Distributed dats bases and data replication are recognised today as an efficient way to increase availability and fiability in data bases. The problem of mutual co-herence of copies is however introduced. Updating data is to be done on all copies. The notion of durability is capital in database. It assume that when a database crash, comited transactions are load on a stable database memory. Durability is a technique of fault tolerance. Another technique of fault tolerance is replication, multiple copies assume that when one of them crash, the rest of copies continue to operate. This two tech-niques has their disavantages in terms of complexity and performance. This semester work, look how durability and replication work together. The performance criteria of the simulation are expressed in terms of the generated traffic, response time and duration of unavailability of copies.