Managing HP Serviceguard A.11.20.20 for Linux, March 2014

• cmlogd—cluster system log daemon
• cmdisklockd—cluster lock LUN daemon
• cmresourced—Serviceguard Generic Resource Assistant daemon
• cmprd—Persistent Reservation daemon
• cmserviced—Service Assistant daemon
• qs—Quorum Server daemon
• cmlockd—utility daemon
• cmsnmpd—cluster SNMP subagent (optionally running)
• cmwbemd—WBEM daemon
• cmproxyd—proxy daemon
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.
NOTE: The file cmcluster.conf contains the mappings that resolve symbolic references to
$SGCONF, $SGROOT, $SGLBIN, etc, used in the pathnames in the subsections that follow. See
“Understanding the Location of Serviceguard Files” (page 135) for details.
3.1.1.1 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).
Parameters are in the /etc/xinetd.d/hacl-cfg and /etc/xinetd.d/hacl-cfgudp files.
The path for this daemon is $SGLBIN/cmclconfd.
3.1.1.2 Cluster Daemon: cmcld
This daemon determines cluster membership by sending heartbeat messages to cmcld daemons
on other nodes in 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 reboot 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 system reset resulting
from the expiration of the safety timer, messages will be written to syslog, and the kernel’s
message buffer, if possible, and a system dump is performed.
The duration of the safety timer depends on the cluster configuration parameter MEMBER_TIMEOUT,
and also on the characteristics of the cluster configuration, such as whether it uses a quorum server
or a cluster lock (and what type of lock) and whether or not standby LANs are configured.
For further discussion, see “What Happens when a Node Times Out” (page 75). For advice on
setting MEMBER_TIMEOUT, see Cluster Configuration Parameters (page 90). For troubleshooting,
see “Cluster Re-formations Caused by MEMBER_TIMEOUT Being Set too Low” (page 262).
cmcld also manages Serviceguard packages, determining where to run them and when to start
them. The path for this daemon is: $SGLBIN/cmcld.
NOTE: Two of the central components of Serviceguard—Package Manager, and Cluster
Manager—run as parts of the cmcld daemon. This daemon runs at priority 94 and is in the
SCHED_RR class. No other process is allowed a higher real-time priority.
34 Understanding Serviceguard Software Components