Managing HP Serviceguard for Linux, Tenth Edition, September 2012

the package to halt and moves the package to an available alternate node. The path
for this daemon is: $SGLBIN/cmserviced.
Generic Resource Assistant Daemon: cmresourced
This daemon is responsible to set and get the status/value of generic resources configured
as part of the package and influence the availability of the package based on the
availability of the resource.
Generic resources allows custom defined monitors to be integrated. It provides better
control, options, and flexibility in terms of getting and setting the status of a resource.
This daemon is used by the Serviceguard commands cmgetresource(1m) and
cmsetresource(1m) to get or set the status/value of a simple/extended generic
resource configured in a package and is local to a node. This daemon runs on every
node on which cmcld is running.
Quorum Server Daemon: qs
Using a quorum server is one way to break a tie and establish a quorum when the cluster
is re-forming; the other way is to use a Lock LUN. See “Cluster Quorum to Prevent
Split-Brain Syndrome” (page 40) and the sections that follow it.
The quorum server, if used, runs on a system external to the cluster. It is normally started
from /etc/inittab with the respawn option, which means that it automatically restarts
if it fails or is killed. It can also be configured as a Serviceguard package in a cluster
other than the one(s) it serves; see Figure 9 (page 42).
All members of the cluster initiate and maintain a connection to the quorum server; if it
dies, the Serviceguard nodes will detect this and then periodically try to reconnect to it.
If there is a cluster re-formation while the quorum server is down and tie-breaking is
needed, the re-formation will fail and all the nodes will halt (system reset). For this reason
it is important to bring the quorum server back up as soon as possible.
For more information about the Quorum Server software and how it works, including
instructions for configuring the Quorum Server as a Serviceguard package, see the latest
version of the HP Serviceguard Quorum Server release notes at http://docs.hp.com
-> High Availability -> Quorum Server. See also “Use of the Quorum Server
as a Cluster Lock” (page 41).
The path for this daemon is:
• For SUSE: /opt/qs/bin/qs
• For Red Hat: /usr/local/qs/bin/qs
Utility Daemon: cmlockd
Runs on every node on which cmcld is running. It maintains the active and pending
cluster resource locks.
36 Understanding Serviceguard Software Components