Managing HP Serviceguard for Linux, Sixth Edition, August 2006

Understanding Serviceguard Software Components
Serviceguard Architecture
Chapter 3 33
Each of these daemons logs to the Linux system logging files. The
quorum server daemon logs to the user specified log file, such as,
/usr/local/qs/log/qs.log file on Red Hat or /var/log/qs/sq.log on
SuSE and cmomd logs to /usr/local/cmom/log/cmomd.log on Red Hat
or /var/log/cmom/log/cmomd.log on SuSE.
Configuration Daemon: cmclconfd
This daemon is used by the Serviceguard commands to gather
information from all the nodes within the cluster. It gathers
configuration information such as information on networks and volume
groups. It also distributes the cluster binary configuration file to all
nodes in the cluster. This daemon is started by the internet daemon,
xinetd(1M).
The path for this daemon is: $SGLBIN/cmclconfd. Relevant parameters
are found in the /etc/xinetd.d/hacl-cfg and
/etc/xinetd.d/hacl-cfgudp files.
NOTE The file /etc/cmcluster.conf contains the mappings that resolve
symbolic references to $SGCONF, $SGROOT, $SGLBIN, etc. See
“Understanding the Location of Serviceguard Files” on page 122 for
details.
Cluster Daemon: cmcld
This daemon is used to determine cluster membership by sending
heartbeat messages to other cmcld daemons on other nodes within the
Serviceguard cluster. It runs at a real time priority and is locked in
memory. The cmcld daemon sets a safety timer in the kernel which is
used to detect kernel hangs. If this timer is not reset periodically by
cmcld, the kernel will cause a system TOC, that is, a Transfer of Control,
which means a CPU reset. This could occur because cmcld could not
communicate with the majority of the cluster’s members, or because
cmcld exited unexpectedly, aborted, or was unable to run for a significant
amount of time and was unable to update the kernel timer, indicating a
kernel hang. Before a TOC due to the expiration of the safety timer,
messages will be written to the syslog file and the kernel’s message
buffer.