EMS Manual

Configuring EMS
EMS Manual—426909-005
12-16
Configuration Issues
Configuration Issues
One of the difficulties in configuring systems and networks is that each decision
requires a balance between two system characteristics. For example, higher
performance must often be weighed against its cost in resource consumption or in
potential loss of data integrity. While not showing you how to avoid such trade-offs, this
subsection describes some of the implications of decisions you might make in
configuring EMS components.
Task Requirements
The most important configuration decision is what tasks the configuration should
support. EMS supports evolutionary decision-making in this respect, so you can add or
change functionality as needed. You can start with just the primary collector and an
initial log-file strategy. (See Log File Operation on page 12-23.)
You can add consumer, forwarding, and printing distributors as you need them. For
each distributor, you must decide what type is appropriate, what filter is required, and
whether to initiate the distributor interactively or programmatically. You can easily
change from one alternative to another. For example, you might run a printing
distributor interactively with a special filter until you decide the filter is correct. When
the filter is working, you can write a management application to handle the event
messages that the filter passes; when the application is working, you can have it
initiate its own consumer distributor programmatically and load the filter.
If messages produced during a system load need to be displayed, add the compatibility
distributor to your system configuration.
Networking Considerations
When your EMS tasks include managing multiple systems in a network, there are
some additional considerations:

How do you see the network, from a management point of view? Is each system
relatively autonomous? Or do you want to monitor all systems from a central
system (a network control node)? The network-control-node configuration naturally
implies the use of one or more forwarding distributors.
To reduce message traffic between nodes, the forwarding distributor transfers
event messages in blocks when it queues more than one message while a
previous message is in transit. Forwarded messages are logged by the collector at
the target node (the remote collector) and are then available for processing by all
distributors monitoring the remote collector’s log file.
If you send only a few messages to another node and choose not to use blocking,
and if the only destination for those messages is a single management application
(so having all distributors process the messages is wasteful), have a local
consumer distributor retrieve those messages and return them to the application
on the remote node. With this configuration, messages might be sent less