Managing HP Serviceguard A.11.20.10 for Linux, December 2012

4 Planning and Documenting an HA Cluster
Building a Serviceguard cluster begins with a planning phase in which you gather and record
information about all the hardware and software components of the configuration.
This chapter assists you in the following planning areas:
• General Planning
• Hardware Planning (page 77)
• Power Supply Planning (page 79)
• Cluster Lock Planning (page 80)
• Volume Manager Planning (page 81)
• Cluster Configuration Planning (page 81)
• Package Configuration Planning (page 100)
Appendix C (page 273) contains a set of blank worksheets which you may find useful as an offline
record of important details of the configuration.
NOTE: Planning and installation overlap considerably, so you may not be able to complete the
worksheets before you proceed to the actual configuration. In that case, fill in the missing elements
to document the system as you proceed with the configuration.
Subsequent chapters describe configuration and maintenance tasks in detail.
4.1 General Planning
A clear understanding of your high availability objectives will quickly help you to define your
hardware requirements and design your system. Use the following questions as a guide for general
planning:
1. What applications must continue to be available in the event of a failure?
2. What system resources (processing power, networking, SPU, memory, disk space) are needed
to support these applications?
3. How will these resources be distributed among the nodes in the cluster during normal operation?
4. How will these resources be distributed among the nodes of the cluster in all possible
combinations of failures, especially node failures?
5. How will resources be distributed during routine maintenance of the cluster?
6. What are the networking requirements? Are all networks and subnets available?
7. Have you eliminated all single points of failure? For example:
• network points of failure.
• disk points of failure.
• electrical points of failure.
• application points of failure.
4.1.1 Serviceguard Memory Requirements
Serviceguard requires approximately 15.5 MB of lockable memory.
4.1.2 Planning for Expansion
When you first set up the cluster, you indicate a set of nodes and define a group of packages for
the initial configuration. At a later time, you may wish to add additional nodes and packages, or
you may wish to use additional disk hardware for shared data storage. If you intend to expand
4.1 General Planning 75