Cluster Daemons; System Monitoring Daemon; B.2 Cluster Daemons - Red Hat CLUSTER MANAGER - INSTALLATION AND Administration Manual

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The complete failure of the heartbeat communication mechanism does not automatically result in
a failover.
If a cluster system determines that the quorum timestamp from the other cluster system is not up-to-
date, it will check the heartbeat status. If heartbeats to the system are still operating, the cluster will
take no action at this time. If a cluster system does not update its timestamp after some period of time,
and does not respond to heartbeat pings, it is considered down.
Note that the cluster will remain operational as long as one cluster system can write to the quorum
disk partitions, even if all other communication mechanisms fail.

B.2 Cluster Daemons

The cluster daemons are as follows:
• Quorum daemon
On each cluster system, the cluquorumd quorum daemon periodically writes a timestamp and
system status to a specific area on the primary and backup quorum disk partitions. The daemon
also reads the other cluster system's timestamp and system status information from the primary
quorum partition or, if the primary partition is corrupted, from the backup partition.
• Heartbeat daemon
On each cluster system, the cluhbd heartbeat daemon issues pings across the point-to-point Eth-
ernet and serial lines to which both cluster systems are connected.
• Power daemon
On each cluster system, the clupowerd power daemon monitors the remote power switch con-
nection, if any. You will notice that there are two separate clupowerd processes running. One is
the master process which responds to message requests (e.g. status and power cycle); the other
process does periodic polling of the power switch status.
• Service manager daemon
On each cluster system, the clusvcmgrd service manager daemon responds to changes in cluster
membership by stopping and starting services. You may notice, at times, that there may be more
than one clusvcmgrd process running. This occurs due to the fact that clusvcmgrd spawns
separate processes for start, stop, and monitoring operations.
•

System monitoring daemon

On each cluster system, the clumibd and xmproxyd daemons respond to cluster monitoring
requests. The Red Hat Cluster Manager GUI is the principal user of these services.
Appendix B:Supplementary Software Information