The registration monitoring features lets you configure GAB behavior when HAD is killed and does not reconnect after a specified time interval.
This scenario may occur in the following situations:
The system is very busy and the hashadow process cannot restart HAD.
The HAD and hashadow processes were killed by user intervention.
The hashadow process restarted HAD, but HAD could not register.
A hardware/DIMM failure causes termination of the HAD and hashadow processes.
Any other situation where the HAD and hashadow processes ae not run.
When this occurs, the registration monitoring timer starts. GAB takes action if HAD does not register within the time defined by the VCS_GAB_RMTIMEOUT parameter, which is defined in the
vcsenv file. The default value for VCS_GAB_RMTIMEOUT is 200 seconds.
When HAD cannot register after the specified time period, GAB logs a message every 15 seconds saying it will panic the system.
You can control GAB behavior in this situation by setting the VCS_GAB_RMACTION parameter in the vcsenv file.
To configure GAB to panic the system in this situation, set:
In this configuration, killing the HAD and hashadow processes results in a panic unless you start HAD within the registration monitoring timeout interval.
To configure GAB to log a message in this situation, set:
The default value of this parameter is SYSLOG, which configures GAB to log a message when HAD does not reconnect after the specified time interval.
In this scenario, you can choose to restart HAD (using hastart) or unconfigure GAB (using gabconfig -U).
When you enable registration monitoring, GAB takes no action if the HAD process unregisters with GAB normally, that is if you stop HAD using the hastop command.