Managing HP Serviceguard for Linux, Seventh Edition, July 2007

Planning and Documenting an HA Cluster
Cluster Configuration Planning
Chapter 4 105
Cluster Configuration Planning
A cluster should be designed to provide the quickest possible recovery
from failures. The actual time required to recover from a failure depends
on several factors:
• The length of the cluster heartbeat interval and node timeout.
See the parameter descriptions for HEARTBEAT_INTERVAL and
NODE_TIMEOUT under “Cluster Configuration Parameters” starting on
page 106 for recommendations.
• The design of the run and halt instructions in the package control
script. They should be written for fast execution.
• The application and database recovery time. They should be
designed for the shortest recovery time.
In addition, you must provide consistency across the cluster so that:
• User names are the same on all nodes.
• UIDs are the same on all nodes.
• GIDs are the same on all nodes.
• Applications in the system area are the same on all nodes.
• System time is consistent across the cluster.
• Files that could be used by more than one node, such as /usr or /opt
files, must be the same on all nodes.