Managing Serviceguard Eighteenth Edition, September 2010

deployed as part of the Serviceguard Storage Management Suite bundles, the file
/etc/gabtab is automatically configured and maintained by Serviceguard.
GAB provides membership and messaging for CVM and the CFS. GAB membership
also provides orderly startup and shutdown of the cluster file system.
• LLT (Low Latency Transport) - When Veritas CVM or CFS is deployed as part of
the Serviceguard Storage Management Suite bundles, the LLT files/etc/llthosts
and /etc/llttab are automatically configured and maintained by Serviceguard.
LLT provides kernel-to-kernel communications and monitors network
communications for CFS.
• vxfend - When Veritas CFS is deployed as part of the Serviceguard Storage
Management Suite, the I/O fencing daemon vxfend is also included. It implements
a quorum-type functionality for the Veritas Cluster File System. vxfend is
controlled by Serviceguard to synchronize quorum mechanisms.
• cmvxd - The Serviceguard-to-Veritas daemon coordinates the membership
information between Serviceguard and Veritas' Clustered File System product.
(Only present when Veritas CFS is installed.)
• cmvxping- The Serviceguard-to-Veritas daemon activates certain subsystems of
the Veritas Clustered File System product. (Only present when Veritas CFS is
installed.)
How the Cluster Manager Works
The cluster manager is used to initialize a cluster, to monitor the health of the cluster,
to recognize node failure if it should occur, and to regulate the re-formation of the
cluster when a node joins or leaves the cluster. The cluster manager operates as a
daemon process that runs on each node. During cluster startup and re-formation
activities, one node is selected to act as the cluster coordinator. Although all nodes
perform some cluster management functions, the cluster coordinator is the central point
for inter-node communication.
Configuring the Cluster
The system administrator sets up cluster configuration parameters and does an initial
cluster startup; thereafter, the cluster regulates itself without manual intervention in
normal operation. Configuration parameters for the cluster include the cluster name
and nodes, networking parameters for the cluster heartbeat, cluster lock information,
and timing parameters (discussed in the chapter “Planning and Documenting an HA
Cluster ” (page 121)). You can set cluster parameters using Serviceguard Manager or
by editing the cluster configuration file (see Chapter 5: “Building an HA Cluster
Configuration” (page 205)). The parameters you enter are used to build a binary
configuration file which is propagated to all nodes in the cluster. This binary cluster
configuration file must be the same on all the nodes in the cluster.
How the Cluster Manager Works 59