Consequences of Open Model

Replication is an area where there is a lot of room for competition between different algorithms. Unfortunately, this means that it may be hard to provide an open system. A key problem is whether a server has to keep state about clients. Depending on a number of design decisions, different distributed filesystems require more or less server state. An open system would imply that all servers must keep state about all clients irrespective of the protocol, since they cannot tell if the client (or other servers) are conspiring to produce the right reliability of service.