Fault Tolerance of the Group Service
The group service is automatically fault-tolerant, if and only if the FTL server is fault-tolerant.
FTL servers automatically start a group service module alongside each realm service.
Group services within a local set of FTL servers automatically coordinate for fault-tolerant operation, and redirect group members to the currently active group service.
A fault-tolerant group service operates with local scope. That is, if an application client of an FTL server could failover to another FTL server in the same local network, then a group member in that client could failover to the corresponding group service in that FTL server.
For example, a fault-tolerant set of primary FTL servers implies a fault-tolerant set of group services that serves the combined clients of those primaries. Similarly, a fault-tolerant set of satellite FTL servers implies a fault-tolerant set of group services that serves the combined clients of those satellites. However, group members cannot cooperate across different local networks.