Managing HP Serviceguard for Linux, Tenth Edition, September 2012

• If you use the reserved CAPACITY_NAME package_limit, weight_name, if
used, must also be package_limit.
• You do not have to define a capacity for every node; if you don't, the node is
assumed to have unlimited capacity and will be able to run any number of eligible
packages at the same time.
• If you want to define only a single capacity, but you want the default weight to be
zero rather than 1, do not use the reserved name package_limit. Use another
name (for example resource_quantity) and follow the Comprehensive Method.
This is also a good idea if you think you may want to use more than one capacity
in the future.
To learn more about configuring weights and capacities, see the documents listed under
For More Information (page 146).
Comprehensive Method
Use this method if the Simple Method (page 139) does not meet your needs. (Make sure
you have read that section before you proceed.) The comprehensive method works best
if packages consume differing amounts of computing resources, so that simple one-to-one
comparisons between packages are not useful.
IMPORTANT: You cannot combine the two methods. If you use the reserved capacity
package_limit for any node, Serviceguard will not allow you to define any other
type of capacity and weight in this cluster; so you are restricted to the Simple Method
in that case.
Defining Capacities
Begin by deciding what capacities you want to define; you can define up to four different
capacities for the cluster.
You may want to choose names that have common-sense meanings, such as “processor”,
“memory”, or “IO”, to identify the capacities, but you do not have to do so. In fact it
could be misleading to identify single resources, such as “processor”, if packages really
contend for sets of interacting resources that are hard to characterize with a single name.
In any case, the real-world meanings 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;
Package Configuration Planning 141