Managing Serviceguard Eighteenth Edition, September 2010

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 20
on all cluster nodes. It is important that user processes should have a priority lower
than 20, otherwise they may prevent Serviceguard from updating the kernel safety
timer, causing a system reset.
File Management Daemon: cmfileassistd
The cmfileassistd daemon is used by cmcld to manage the files that it needs to
read from, and write to, disk. This is to prevent any delays in issuing Input/Output
from impacting the timing of cmcld.
Syslog Log Daemon: cmlogd
cmlogd is used by cmcld to write messages to syslog. Any message written to
syslog by cmcld is written via cmlogd. This is to prevent any delays in writing to
syslog from affecting the timing of cmcld.
Cluster Logical Volume Manager Daemon: cmlvmd
This daemon is responsible for keeping track of all the volume group(s) that have been
made cluster aware. When a volume group is made cluster aware, a cluster node can
only activate it in exclusive mode. This prevents the volume group from being activated
in write mode by more than one node at a time.
Cluster Object Manager Daemon: cmomd
This daemon is responsible for providing information about the cluster to
clients—external products or tools that depend on knowledge of the state of cluster
objects.
Clients send queries to the object manager and receive responses from it (this
communication is done indirectly, through a Serviceguard API). The queries are
decomposed into categories (of classes) which are serviced by various providers. The
providers gather data from various sources, including, commonly, the cmclconfd
daemons on all connected nodes, returning data to a central assimilation point where
it is filtered to meet the needs of a particular query.
This daemon is started by inetd(1M). There are entries in the /etc/inetd.conf
file.
This daemon may not be running on your system; it is used only by clients of the object
manager.
Cluster SNMP Agent Daemon: cmsnmpd
This daemon collaborates with the SNMP Master Agent to provide instrumentation
for the cluster Management Information Base (MIB).
56 Understanding Serviceguard Software Components