Availability Guide for Application Design

Instrumenting an Application for Availability
Availability Guide for Application Design—525637-004
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The DSM Subsystem Environment
Creating a Data Definition File
From the data definition file, you create SPI definitions for your tokens in the language
in which your application is written. If you choose to use standard event messages, a
sample DDL file is available through Infoway. You can copy this file and modify it to
suit your needs.
Building Event Messages
To build and generate an event message using EMS or SPI procedures, your program
must contain logic to:
•
Open the EMS collector
•
Build the event message
•
Send the event message to the collector
•
Close the EMS collector
Your program will typically open and close the EMS collector only once. With the EMS
collector open, it will build and send event messages to the collector as required.
To build event messages, you must define a buffer as a sequence of tokens. Each
token provides one element of information that needs to be sent to EMS as part of the
message. If you are not using standard event messages, you must use SPI procedures
to initialize an event message buffer with the default tokens required by all EMS
messages, and then add any other tokens you need to include.
Using SPI Programming for a Command-and-Response
Interface
Your application environment must include a command-and-response interface if it is
to be able to respond to commands issued by management applications. This module
must perform the same kinds of functions for your application environment as a
subsystem management interface supplied by HP does for a HP subsystem.
The application management interface is a server process that accepts requests from
a management application, which might be a commercial product such as the
ViewPoint product, or it might be an application you wrote yourself. The requester and
server communicate with each other using Guardian interprocess communication as
described in the Guardian Programmer’s Guide.
A brief overview of how you can help increase the availability of your application
through using SPI programming to write an application management interface is given
here. For full details on how to write a management interface server for your
application, including hints on contingencies you might need to design for, refer to the
SPI Programming Manual.
When to Use SPI Programming for an Application Management Interface
Any application that needs to be controlled by a management application needs an
application management interface. SPI programming provides such an interface.