EMS Manual

Introduction to EMS
EMS Manual—426909-005
1-7
Key Features

Subsystem generality. Each EMS message has a number of elements called
tokens. Each token consists of a data value and an associated tag that identifies
the data value. All subsystems use tokens to build event messages, thus ensuring
that messages have the same general format and present similar information in
similar ways. For example, EMS requires that all subsystems specify the subject of
the event (the primary component involved in the event) in an event message.
Thus, a management application can always locate the subject token by
requesting it in a standard way. Also, EMS defines conventions for reporting critical
events and action events (situations requiring operator action) to ensure that these
types of events are recognized in the operations environment.

Ease of use. Interfaces to EMS use standard file-system procedure calls and,
where applicable, standard SPI message formats and conventions. To help you
write subsystems that report events, EMS includes procedures that initialize and
add tokens to event messages. To help you obtain text for display, EMS includes a
procedure that returns the text defined for an event message.

Versatility. You can use EMS for many types of applications because of the variety
of options it provides:

EMS supports applications that monitor events as they occur, as well as
applications that analyze logs of event messages reported in the past.

Distributor processes are provided for communicating event messages to
management applications, forwarding event messages from one node to
another, and displaying event-message text on printers and other display
devices.

Filtering lets you select event messages of interest to each application, based
on whatever event-message tokens and values you choose.

EMS provides event information in token form for programmatic use or in text
form for operator display. Event information in token form is also known as
tokenized event information. Tokenized event information consists of machine
readable tokens that are generated by the primary collector ($0). Untokenized
messages are used to provide compatibility with pre-EMS systems.

EMS supports both HP and user-written subsystems. If the user-written
subsystems running on your system or network follow the same conventions
as subsystems for the NonStop server, EMS can provide you with an
integrated picture of the subsystem environment.

Configuration flexibility. EMS supports a wide variety of configurations, so you can
select the configuration that best meets the requirements of your data processing
environment:

EMS lets you distribute event-message processing among network nodes and
among processors on a single node. Event messages can be distributed from
one node to another. SPI interfaces, such as those used to control EMS
processes and those used to retrieve event messages, can cross node
boundaries.