Managing Serviceguard 11th Edition, Version A.11.16, Second Printing June 2004

Understanding Serviceguard Software Components
Serviceguard Architecture
Chapter 3 61
This will only be running if the /etc/rc.config.d/cmsnmpagt file has
been edited to autostart this subagent. For proper execution, the
cmsnmpd has to start before the Serviceguard cluster comes up.
Service Assistant Daemon: cmsrvassistd
This daemon forks and execs any script or processes as required by the
cluster daemon, cmcld. There are two type of forks that this daemon
carries out:
• Executing package run and halt scripts
• Launching services
For services, cmcld monitors the service process and, depending on the
number of service retries, cmcld either restarts the service through
cmsrvassistd or it causes the package to halt and moves the package to
an available alternate node.
Shared Tape Daemon: cmtaped
The shared tape daemon is responsible for keeping track of all the shared
tape devices that are part of the cluster. Share tape devices can be
configured using the stapplyconf command.
Quorum Server Daemon: qs
The quorum server daemon provides tie-breaking services when needed
during cluster re-formation. The quorum server runs on a system
external to the cluster, and it is started by the user, not by Serviceguard.
It is normally started out of /etc/inittab, which means that it
automatically re-spawns if it fails or is killed.
All members of the cluster initiate and maintain a connection to the
quorum server. If the quorum server dies, the Serviceguard nodes will
detect this and then periodically try to reconnect to the quorum server
until it comes back up. If there is a cluster reconfiguration while the
quorum server is down and there is a partition in the cluster that
requires tie-breaking, the reconfiguration will fail.