Managing HP Serviceguard for Linux Ninth Edition, April 2009

in each case. You may want to set CAPACITY_VALUE to different values for different
nodes. A ten-package capacity might represent the most powerful node, for example,
while the least powerful has a capacity of only two or three.
NOTE: Serviceguard does not require you to define a capacity for each node. If you
define the CAPACITY_NAME and CAPACITY_VALUE parameters for some nodes but
not for others, the nodes for which these parameters are not defined are assumed to
have limitless capacity; in this case, those nodes would be able to run any number of
eligible packages at any given time.
If some packages consume more resources than others, you can use the weight_name
and weight_value parameters to override the default value (1) for some or all packages.
For example, suppose you have three packages, pkg1, pkg2, and pkg3. pkg2 is about
twice as resource-intensive as pkg3 which in turn is about one-and-a-half times as
resource-intensive as pkg1. You could represent this in the package configuration files
as follows:
• For pkg1:
weight_name package_limit
weight_value 2
• For pkg2:
weight_name package_limit
weight_value 6
• For pkg3:
weight_name package_limit
weight_value 3
Now node1, which has a CAPACITY_VALUE of 10 for the reserved CAPACITY_NAME
package_limit, can run any two of the packages at one time, but not all three. If in
addition you wanted to ensure that the larger packages, pkg2 and pkg3, did not run
on node1 at the same time, you could raise the weight_value of one or both so that the
combination exceeded 10 (or reduce node1's capacity to 8).
Points to Keep in Mind
The following points apply specifically to the Simple Method (page 129). Read them in
conjunction with the Rules and Guidelines (page 136), which apply to all weights and
capacities.
130 Planning and Documenting an HA Cluster