Installation guide

176 Appendix B:Supplementary Software Information
If a quorum daemon fails, and power switches are used in the cluster, the following occurs:
1. The functional cluster system detects that the cluster system whose quorum daemon has failed is
not updating its timestamp on the quorum partitions, although the system is still communicating
over the heartbeat channels.
2. After a period of time, the functional cluster system power-cycles the cluster system whose quorum
daemon has failed. Alternatively, if watchdog timers are in use, the failed system will reboot itself.
3. The functional cluster system restarts any services that were running on the cluster system whose
quorum daemon has failed.
4. If the cluster system reboots and can join the cluster (that is, it can write to the quorum partitions),
services are re-balanced across the member systems, according to each service’s placement policy.
If a quorum daemon fails, and neither power switches nor watchdog timers are used in the cluster, the
following occurs:
1. The functional cluster system detects that the cluster system whose quorum daemon has failed is
not updating its timestamp on the quorum partitions, although the system is still communicating
over the heartbeat channels.
2. The functional cluster system restarts any services that were running on the cluster system whose
quorum daemon has failed. Under the unlikely event of catastrophic failure, both cluster systems
may be running services simultaneously, which can cause data corruption.
B.3.7 Heartbeat Daemon Failure
If the heartbeat daemon fails on a cluster system, service failover time will increase because the quo-
rum daemon cannot quickly determine the state of the other cluster system. By itself, a heartbeat
daemon failure will not cause a service failover.
B.3.8 Power Daemon Failure
If the power daemon fails on a cluster system and the other cluster system experiences a severe failure
(for example, a system panic), the cluster system will not be able to power-cycle the failed system.
Instead, the cluster system will continue to run its services, and the services that were running on the
failed system will not fail over. Cluster behavior is the same as for a remote power switch connection
failure.
B.3.9 Service Manager Daemon Failure
If the service manager daemon fails, services cannot be started or stopped until you restart the service
manager daemon or reboot the system. The simplest way to restart the service manager is to first
stop the cluster software and then restart it. For example, to stop the service, perform the following
command: