Managing Serviceguard A.11.20, March 2013

You define weights for individual packages in the package configuration file, but you can also
define a cluster-wide default value for a given weight, and, if you do, this default will specify the
weight of all packages that do not explicitly override it in their package configuration file.
NOTE: There is one exception: system multi-node packages cannot have weight, so a cluster-wide
default weight does not apply to them.
Defining Default Weights
To pursue the example begun under “Defining Capacities” (page 152), let's assume that all packages
other than pkg1 and pkg2 use about the same amount of capacity A, and all packages other than
pkg3 and pkg4 use about the same amount of capacity B. You can use the WEIGHT_DEFAULT
parameter in the cluster configuration file to set defaults for both weights, as follows.
Example 3
WEIGHT_NAME A
WEIGHT_DEFAULT 20
WEIGHT_NAME B
WEIGHT_DEFAULT 15
This means that any package for which weight A is not defined in its package configuration file
will have a weight A of 20, and any package for which weight B is not defined in its package
configuration file will have a weight B of 15.
Given the capacities we defined in the cluster configuration file (see “Defining Capacities”), node1
can run any three packages that use the default for both A and B. This would leave 20 units of
spare A capacity on this node, and 5 units of spare B capacity.
Defining Weights for Individual Packages
For each capacity you define in the cluster configuration file (see “Defining Capacities”) you have
the following choices when it comes to assigning a corresponding weight to a given package:
1. Configure a cluster-wide default weight and let the package use that default.
2. Configure a cluster-wide default weight but override it for this package in its package
configuration file.
3. Do not configure a cluster-wide default weight, but assign a weight to this package in its
package configuration file.
4. Do not configure a cluster-wide default weight and do not assign a weight for this package
in its package configuration file.
NOTE: Option 4 means that the package is “weightless” as far as this particular capacity is
concerned, and can run even on a node on which this capacity is completely consumed by other
packages.
(You can make a package “weightless” for a given capacity even if you have defined a cluster-wide
default weight; simply set the corresponding weight to zero in the package's cluster configuration
file.)
Pursuing the example started under “Defining Capacities” (page 152), we can now use options 1
and 2 to set weights for pkg1 through pkg4.
Example 4
In pkg1's package configuration file:
weight_name A
weight_value 60
In pkg2's package configuration file:
154 Planning and Documenting an HA Cluster