OVNM 5.3 - Operations Agent for NonStop Event Management Guide for Windows

HP NonStop Event Management System 15
Basic Capabilities
EMS supports many aspects of managing event messages, from generation of a message in the subsystem
environment to generation of text for display in the operations environment. This list describes the basic EMS
capabilities, in the approximate order in which they would apply to a single event message:
• Message building
EMS includes several library procedures that HP NonStop subsystems, and subsystems you write use to
build event messages. One procedure initializes a buffer, ensuring that a message has the correct format
and providing some of the standard information found in all event messages. The subsystem then calls other
procedures to add different kinds of information to the event message.
• Message collection, filtering, and logging
The EMS primary and alternate collectors accept event messages from subsystems, use pre-log filtration
(PLF) for specific event messages, use burst detection and suppression (BDS) to suppress specified types of
event bursts, and write unfiltered events to log files. Pre-log filtration makes use of compiled filters or filter
tables to totally suppress the logging of certain event types.
• Message filtering and distribution
The EMS distributor processes provide:
• Selection (or filtering) of event messages
• Use of burst filters to implement BDS on specified types of event bursts
• Distribution of event messages to their destination devices
As with collector filters, filtering in distributors is the process of evaluating event messages and selecting
only those in which a particular requester has expressed interest. Distribution is the returning of a selected
event message to a requester through the appropriate interface. EMS can distribute event messages to
processes, files, collectors on other nodes, and display devices such as terminals and printers.
• Text formatting
EMS includes a procedure that returns text suitable for display to an operator.
Key Features
EMS has many significant characteristics that help you manage your system or network:
• 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.
HP NonStop Event Management System