VERITAS Volume Manager 4.1 Administrator's Guide

Administering Cluster Functionality
Cluster Initialization and Configuration
Chapter 10 361
held up and restarted later. In most cases, cluster reconfiguration takes
precedence. However, if the volume reconfiguration is in the commit
stage, it completes first.
For more information on cluster reconfiguration, see “vxclustd Daemon”
on page 361
vxclustd Daemon
The vxclustd daemon is the VxVM cluster reconfiguration daemon. The
vxclustd daemon provides communication between the cluster monitor
and VxVM, and initiates cluster reconfiguration. Every node currently in
the cluster runs an instance of the vxclustd daemon. Whenever cluster
membership changes, the cluster monitor notifies the vxclustd daemon,
which then initiates a reconfiguration within VxVM.
The vxclustd daemon is started up by the cluster monitor when the node
initially attempts to join the cluster. The vxclustd daemon first registers
with the cluster monitor and obtains the following information from the
cluster monitor:
• cluster ID and cluster name
• node IDs and hostnames of all configured nodes
• IP addresses of the network interfaces through which the nodes
communicate with each other
Registration also sets up a callback mechanism for the cluster monitor to
notify the vxclustd daemon when cluster membership changes. After
initializing kernel cluster variables, the vxclustd daemon waits for a
callback from the cluster monitor. When the vxclustd daemon obtains
membership information from the cluster monitor, it validates the
membership change, and provides the new membership to the kernel.
The reconfiguration process continues within the kernel and the
vxconfigd daemon. This includes selection of a new master node if
necessary, initiation of communication between vxconfigd daemons on
the master and slave nodes, and a join protocol at the vxconfigd and
kernel levels that validates VxVM objects and distributes VxVM
configuration information across the cluster.
If reconfiguration completes successfully, the vxclustd daemon does not
take any further action; it waits for the next membership change from
the cluster monitor. If reconfiguration within the kernel or within the
vxconfigd daemon fails, the node must leave the cluster. The kernel