Availability Guide for Application Design

Instrumenting an Application for Availability
Availability Guide for Application Design—525637-004
8-19
The Subsystem Programmatic Interface (SPI)
•
The DSM operations environment
Applications and tools in the operations environment are available to your
operations staff. In addition to the commercial applications written for DSM, you
can write your own custom management applications to manage HP subsystems
and your business applications. Some DSM tools provide interactive access to
subsystems and the objects they control; others help you write your own SPI
management interfaces to your business applications.
Figure 8-6 shows a typical example of DSM message flow. The business
application generates an EMS message and sends it to EMS. EMS logs the
message and sends it to a distributor process from where it is read by the
automated operator. The automated operator responds to the message by sending
a command to the SPI interface of the business application in the form of an SPI
message.
The Subsystem Programmatic Interface (SPI)
SPI interfaces use token-based messages to deliver information within the DSM
subsystem. Each message element is known as a token that consists of a tag
indicating the purpose of the element and a value. Tokenized messages enable
reliable automated message handling because the tokens are not position dependent.
SPI messages are used to indicate the following actions:
•
Events generated by components of the subsystem environment.
Events are indicated by a special type of SPI message known as an Event
Management Service (EMS) message
•
Commands issued from the operations environment by management applications
to monitor and control objects in the subsystem environment
•
Responses issued by components of the subsystem environment to management
applications in response to commands
Figure 8-6. DSM Message Flow
Automated
Operator
EMS
Objects
Business
Application
Management Services
Operations Environment
Subsystem Environment
EMS
Message
EMS
Message
SPI Message
Log File
VST706.vdd