Hitachi

JP1 Version 12 JP1/Integrated Management 2 - Manager Overview and System Design Guide


4.3 Issue of correlation events

JP1/IM - Manager can issue a new JP1 event whenever two or more related JP1 events are issued. The new event is known as a correlation event. The correlation event and the association between the JP1 events can be defined by the user as a correlation event generation definition.

The related JP1 event that triggers the correlation event is known as a correlation source event. You can define multiple correlation source events, or just one.

For example, suppose JP1/IM - Manager is managing Web servers in a cluster system. If a failure occurs in succession on both the primary node and secondary node, the service provided by the Web servers on these nodes will stop. By associating the JP1 event reporting a failure on the primary node with the JP1 event reporting a failure on the secondary node, and defining a correlation event, you can ensure a speedy response.

The following figure shows the relationships between a correlation event, correlation event generation definition, and correlation source events, based on the above Web server example.

Figure 4‒17: Relationships between correlation event, correlation event generation definition, and correlation source events

[Figure]

The JP1 events issued from the Web servers on the primary and secondary nodes are sent to the manager. The two JP1 events are associated and a correlation event is issued, according to the correlation event generation definition. The JP1 events that triggered the correlation event are known as correlation source events.

There are two kinds of correlation events: A correlation approval event is issued when a correlation is established; a correlation failure event is issued when no correlation is established.

Event issued when a correlation is established

You can issue a correlation approval event when the specified events all arrive within a set timeout period, as in these examples:

  1. Two Web servers are configured in a cluster system. Errors on the primary node issue event A, and errors on the secondary node issue event B.

  2. To detect that services on the Web servers have stopped, write a correlation event generation definition that issues a correlation approval event (event C) when both event A and event B are issued.

Event issued when no correlation is established

You can issue a correlation failure event when the specified events do not all arrive within the timeout period, as in these examples:

  1. Two Web servers are configured in a cluster system. Errors on the primary node issue event A, and errors that occur at failover to the secondary node issue event B.

  2. To detect that services on the Web servers have stopped, write a correlation event generation definition that issues a correlation failure event (event C) if event B does not arrive within the set timeout period after event A is issued.

The JP1 events registered with the JP1/Base event database are acquired by JP1/IM - Manager through an event acquisition filter. JP1/IM - Manager then issues correlation events, based on the settings in the correlation event generation definition. These correlation events are also registered with the JP1/Base event database. This processing is known as correlation event issue.

The following figure shows an overview of correlation event issue.

Figure 4‒18: Overview of correlation event issue

[Figure]

The following describes correlation event issue in further detail.

Organization of this section