206 Event Management and Best Practices
are compared from top to bottom. In situations where there are multiple matching
classes for a message, the last matching format specification is used. If no match
is found, the event is discarded.
A format file also serves as the source from which a CDS file is generated.
Class definition statement file
CDS files are used by an adapter to map incoming raw events to a particular
class and to define event attributes before forwarding the event to the event
server. No alterations to this file are necessary to use an adapter unless you alter
the corresponding .fmt file (if any). If any event definition is changed in a CDS file,
the corresponding event class definition in the BAROC file may also need
IBM Tivoli Enterprise Console gateways
IBM Tivoli Enterprise Console gateways should be placed as close to their
corresponding event sources as possible. Depending on the amount of
processing required for each gateway, including the new features of state
correlation, if enabled, you may need to investigate the performance of each
gateway to ensure that it is capable of managing the number of events and their
respective correlation that it receives from it various event sources.
During our laboratory examples, we did not find or investigate any performance
issues caused by the enablement of state correlation on an IBM Tivoli Enterprise
Console gateway. Of course, our environment does not map exactly to your
existing environment, and we did not run performance tests or scalability tests
during our exercises. You made need to investigate this feature of the IBM Tivoli
Enterprise Console gateways to ensure that you do not experience problems in a
Matching rules are stateless. This means that they perform passive filtering on
the attribute values of an incoming event. A matching rule consists of a single
predicate. If the predicate evaluates to true, the trigger actions, which are
specified in the rule, are executed.
For example, a good practice is to create a state correlation rule, with a match
predicate, to filter events from default root event classes such as EVENT or
Note: IBM Tivoli Enterprise Console Gateway state correlation can apply to all
NetView, TME, and non-TME events received by the IBM Tivoli Enterprise