Managing HP Serviceguard for Linux, Sixth Edition, August 2006

Planning and Documenting an HA Cluster
General Planning
Chapter 488
Serviceguard Memory Requirements
The amount of lockable memory required for Serviceguard for Linux
depends on the number of packages and resources configured in the
cluster. To calculate a rough estimate of how much lockable memory is
needed:
Total Memory = 6 MB (for the HP Serviceguard for Linux base) + 80 KB
(for each package in the cluster)
For example, if you have 10 packages in the cluster, you would require
800 KB (80x10), plus 6 MB for a total of 6.80 MB.
The total amount is needed on each node in the cluster, regardless of
whether a given package or resource is on that node or not.
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 your cluster without the need to bring it down, careful planning
of the initial configuration is required. Use the following guidelines:
• Set the Maximum Configured Packages parameter (described later
in this chapter in the “Cluster Configuration Planning” section) high
enough to accommodate the additional packages you plan to add.
Keep in mind that adding package capacity uses memory resources
(80K per package).
• Networks should be pre-configured into the cluster configuration if
they will be needed for packages you will add later while the cluster
is running.
Refer to the chapter on “Cluster and Package Maintenance” for more
information about changing the cluster configuration dynamically, that
is, while the cluster is running.