VERITAS Volume Manager 3.1 Administrator's Guide

Cluster Functionality
Cluster-related Volume Manager Utilities and Daemons
Chapter 7 319
• 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 provides a callback mechanism for the cluster manager
to notify the vxclustd daemon when cluster membership changes. After
initializing kernel cluster variables, the vxclustd daemon waits for a
callback from the cluster manager. When the vxclustd daemon obtains
membership information from the cluster manager, 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 manager. If reconfiguration within the kernel or within the
vxconfigd daemon fails, the node must leave the cluster. The kernel
fails I/Os in progress to shared disks, and stops access to shared disks
and the vxclustd daemon. The vxclustd daemon invokes the cluster
manager command to halt the cluster on this node.
When a clean node shutdown is performed, the vxclustd daemon waits
until kernel cluster reconfiguration completes and then exits.
vxconfigd Daemon
The vxconfigd daemon is the Volume Manager configuration daemon.
The vxconfigd daemon maintains configurations of VxVM objects. The
Notes:
• If MC/ServiceGuard is the cluster manager, it expects the vxclustd
daemon registration to complete within a given timeout period. If
registration times out, MC/ServiceGuard aborts cluster initialization
and fails cluster startup.
• When performing a clean node shutdown using MC/ServiceGuard’s
cmhaltnode command, VxVM kernel reconfiguration does not
complete until all I/Os to shared disks have completed. This can take
a long time, causing MC/ServiceGuard to time out.