GAB provides various configuration and tunable parameters to modify and control the behavior of the GAB module.

See About Group Membership Services/Atomic Broadcast (GAB).

These tunable parameters not only provide control of the configurations like maximum possible number of nodes in the cluster, but also provide control on how GAB behaves when it encounters a fault or a failure condition. Some of these tunable parameters are needed when the GAB module is loaded into the system. Any changes to these load-time tunable parameters require either unload followed by reload of GAB module or system reboot. Other tunable parameters (run-time) can be changed while GAB module is loaded, configured, and cluster is running. Any changes to such a tunable parameter will have immediate effect on the tunable parameter values and GAB behavior.

These tunable parameters are defined in the following file:

/etc/sysconfig/gab

See About GAB load-time or static tunable parameters.

See About GAB run-time or dynamic tunable parameters.