Program guide > (deprecated) Partitioning facility > Manage the partitioning facility environment > Relation of a partition to an HA group


Deprecated feature: The partitioning facility (WPF) feature is deprecated. You can configure partitioning with WebSphere eXtreme Scale.


Too many policies

The number of policies available in the default core group of the highly available (HA) manager affects performance. Each time the policy is invoked, an action must be applied to a HA manager group (a single partition is a HA group). The default number of partitioning facility (WPF) policies is two, cluster scoped and node scoped policies. You can create an enumerable number of unique policies that meet the requirements. However, when the HA manager attempts to apply the policies it must search through all policies available and determine which one best applies to a specific HA group.

In general, the suggested approach to policies is to use what you need, but only that many. For example, in the case of the demonstration key based sample, a unique policy was created per partition to control the startup of the application to a given application server in the cluster. If the application had 10,0000 partitions, that would require 10,000 policies. This is obviously not the approach a programmer and administrator should take.

Few policies can be used using additional member properties. One of the createPartitionDefinition(...) API signatures can have a Map of additional attributes provided. These properties could help reduce the number of policies. For example, if the user created a new attribute called startOn, and the value could be a string that represents server# where # is a number representing one of the cluster members. The policy could then specify the default already provided in the cluster scoped policy (-gt=-p, -ps=-c), but also (startOn=server4). This would provide three match criteria, and enable # of policies versus 10,000 partitions. If there were 30 servers, for example, to start the partitions on, there could be 30 policies, each with a third match set criteria and the preferred server to be server4. See the wpfadmin policy commands for an example, or the example above if you have not gone through the tutorial.


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Relation of a partition to an HA group


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Relation of a partition to an HA group