Managing HP Serviceguard A.12.00.00 for Linux, June 2014

When designing a storage configuration using VxVM disk groups, consider the following:
• High availability applications, services, and data must be placed in separate disk groups from
non-high availability applications, services, and data.
• You must not group two different high availability applications, services, or data, whose control
needs to be transferred independently, onto the same disk group.
• Your root disk can belong to an LVM or VxVM volume group that is not shared among cluster
nodes.
4.8 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 MEMBER_TIMEOUT; see the description of this parameter under “Cluster
Configuration Parameters” 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.
4.8.1 Easy Deployment
Easy deployment is a feature that provides a quick and simple way to create a cluster. Easy
deployment automates the security, shared storage, and networking configuration required by the
package and cluster. Also, easy deployment simplifies cluster lock configuration. These can be
achieved by using cmquerycl, cmpreparestg, and cmdepolycl commands as described
in the following sections.
4.8.1.1 cmquerycl -N
The cmquerycl queries available network configuration and generates network template.
Example
cmquerycl –n node1 –n node2 –N <network_template_file>
The template file generated from the previous command must be populated with the appropriate
IP addresses and subnet details. This file is then provided as input to the cmdeploycl command
(see section “cmdeploycl”) which applies the network configuration during cluster creation.
4.8.1.2 cmpreparestg
The cmpreparestg creates LVM volume groups and VxVM disk groups from available shared
disks. It can also modify existing LVM volume groups and VxVM disk groups that are configured
on one or more of the cluster nodes. For more information, see cmpreparestg (1m) manpage.
84 Planning and Documenting an HA Cluster