Managing Serviceguard Eighteenth Edition, September 2010

4 Planning and Documenting an HA Cluster
Building a Serviceguard cluster begins with a planning phase in which you gather
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 122)
• Power Supply Planning (page 128)
• Using a Quorum Server (page 130)
• LVM Planning (page 132)
• CVM and VxVM Planning (page 134)
• Cluster Configuration Planning (page 135)
• Package Configuration Planning (page 168)
Blank Planning Worksheets (page 463) 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.
General Planning
A clear understanding of your high availability objectives will 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.
General Planning 121