Managing Serviceguard A.11.20, March 2013

Suppose you have the following configuration:
• A two node cluster running four packages. These packages contend for resource we'll simply
call A and B.
• node1 has a capacity of 80 for A and capacity of 50 for B.
• node2 has a capacity of 60 for A and capacity of 70 for B.
• pkg1 uses 60 of the A capacity and 15 of the B capacity.
• pkg2 uses 40 of the A capacity and 15 of the B capacity.
• pkg3 uses insignificant amount (zero) of the A capacity and 35 of the B capacity.
• pkg4 uses 20 of the A capacity and 40 of the B capacity.
pkg1 and pkg2 together require 100 of the A capacity and 30 of the B capacity. This means
pkg1 and pkg2 cannot run together on either of the nodes. While both nodes have sufficient B
capacity to run both packages at the same time, they do not have sufficient A capacity.
pkg3 and pkg4 together require 20 of the A capacity and 75 of the B capacity. This means pkg3
and pkg4 cannot run together on either of the nodes. While both nodes have sufficient A capacity
to run both packages at the same time, they do not have sufficient B capacity.
Example 2
To define these capacities, and set limits for individual nodes, make entries such as the following
in the cluster configuration file:
CLUSTER_NAME cluster_23
...
NODE_NAME node1
...
CAPACITY_NAME A
CAPACITY_VALUE 80
CAPACITY_NAME B
CAPACITY_VALUE 50
NODE_NAME node2
CAPACITY_NAME A
CAPACITY_VALUE 60
CAPACITY_NAME B
CAPACITY_VALUE 70
...
NOTE: You do not have to define capacities for every node in the cluster. If any capacity is not
defined for any node, Serviceguard assumes that node has an infinite amount of that capacity. In
our example, not defining capacity A for a given node would automatically mean that node could
run pkg1 and pkg2 at the same time no matter what A weights you assign those packages; not
defining capacity B would mean the node could run pkg3 and pkg4 at the same time; and not
defining either one would mean the node could run all four packages simultaneously.
When you have defined the nodes' capacities, the next step is to configure the package weights;
see “Defining Weights”.
Defining Weights
Package weights correspond to node capacities, and for any capacity/weight pair,
CAPACITY_NAME and weight_name must be identical.
Package Configuration Planning 153