Managing HP Serviceguard A.11.20.00 for Linux, June 2012

of the names you assign to node capacities and package weights are outside the scope of
Serviceguard. Serviceguard simply ensures that for each capacity configured for a node, the
combined weight of packages currently running on that node does not exceed that capacity.
For example, if you define a CAPACITY_NAME and weight_name processor, and a
CAPACITY_NAME and weight_name memory, and a node has a processor capacity of 10
and a memory capacity of 1000, Serviceguard ensures that the combined processor weight
of packages running on the node at any one time does not exceed 10, and that the combined
memory weight does not exceed 1000. But Serviceguard has no knowledge of the real-world
meanings of the names processor and memory; there is no mapping to actual processor and
memory usage and you would get exactly the same results if you used the names apples and
oranges.
For example, 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
...
110 Planning and Documenting an HA Cluster