Managing HP Serviceguard A.11.20.20 for Linux, May 2013

• You must not group two different high availability applications, services, or data, whose control
needs to be transferred independently, on the same volume group.
• Your root disk must not belong to a volume group that can be activated on another node.
4.6.1 Volume Groups and Physical Volume Worksheet
You can organize and record your physical disk configuration by identifying which physical disks,
LUNs, or disk array groups will be used in building each volume group for use with high availability
applications. Use the Volume Group and Physical Volume worksheet (page 282).
NOTE: HP recommends that you use volume group names other than the default volume group
names (vg01, vg02, etc.). Choosing volume group names that represent the high availability
applications they are associated with (For example, /dev/vgdatabase) will simplify cluster
administration.
4.7 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.
4.7.1 Easy Deployment: cmpreparecl
The cmpreparecl script allows you to ease the process of setting up the servers participating in
the cluster. It also checks for the availability of ports used by Serviceguard Linux, starts the xinetd
services, updates specific files, and sets up the firewall. As of Serviceguard A.11.20.10, the
cmpreparecl script is supported.
NOTE: After you run the cmpreparecl script, you can start the cluster configuration.
Advantages
• Simple ways to configure the system before you create a cluster.
• Configuration for all the nodes can be done from one of the nodes in the cluster.
Limitations
• All the nodes that are part of the cluster must be known before hand.
86 Planning and Documenting an HA Cluster