Creating standard, hybrid, collector, consumer parameters

This topic provides information about creating standard, hybrid, collector and consumer parameters.

• • Creating a standard parameter
  • PSL functions used in standard parameter scripts
  • Creating a hybrid parameter
  • Creating a collector parameter
  • Creating a consumer parameter

Creating a standard parameter

Create a standard parameter to do the following things:

• Gather data about a single monitored attribute that it displays
• Provide alerts when the attribute measured by the parameter indicates a problem is developing
• Provide recovery actions to correct the problem indicated by the alerts

 Standard parameter programming requirements

This section summarizes the requirements for defining PATROL standard parameters. You must include the following items in an standard parameter definition:

• define each standard parameter's display style (graph, gauge, text, stoplight, Boolean state, or no output)
• set each standard parameter's data collection schedule--either a polling cycle or an event-trigger

 Standard parameter programming guidelines

Consider the following guidelines in defining standard parameters:

• Add a Title and set the Units properties in the Parameter General properties for each standard and consumer parameter.
   Most parameter display styles are more usable if they have a title and a units legend.
• Set the parameter's "History Level" option to Inherited.
   The setting for the retention of historical data should be a user configuration issue rather than a development decision.
• Each standard parameter should have a Border Range set, especially if Alarm1 and Alarm2 ranges are enabled.
• For a parameter for which the default 0-to-100 Range Limits range is not correct, you should reset its Range Limits value and possibly activate the Auto Scale feature on the parameter's Parameter Properties, Alarm Ranges tab.

PSL functions used in standard parameter scripts

The following table lists functions that are often used in standard parameter command scripts.

 Common PSL functions used in standard parameter scripts

Function	Definition
set()	Assigns a value to the specified PATROL Agent namespace variable. The variable's assigned value is available as long as the PATROL Agent is running and the application class is loaded.
get()	Returns the value of a specified PATROL Agent namespace variable or PATROL Agent pconfig database. Use this function in recovery actions to set up conditional corrective actions based on the status of a related parameter or parameters obtained from the PATROL Agent namespace.
popen()	Opens a PSL process channel that spawns a process to execute a command of a defined type and returns the channel number which can be used to read the command's output or return.

Creating a hybrid parameter

The PATROL product allows you to create variants on the standard parameter in order to perform specific monitoring tasks. The following table summarizes hybrid parameters and their usage. 

Hybrid parameter types and usage 

Creating a collector parameter

Create a collector parameter to gather multiple data values for consumer parameters to display. Using collector parameters is the most efficient way to gather data to populate multiple consumer parameters. By populating consumer parameters with data, problem determination and correction can be defined at a very precise level. In this section, collector parameter definition is explored.

Encapsulating collectors

In some situations, it is better to encapsulate all parameter collectors in an application that gathers data for all the consumer parameters in the application.

Creating a consumer parameter

Define a consumer parameter to divide collector data into specific matrixes with its own:

• Alarm ranges
• Recovery actions
• Data retention (history)

Creating collector/consumer parameter groups offers many benefits including:

• Improved PATROL KM efficiency and performance
• Precise problem determination and correction

 Consumer parameter programming guidelines

Consider the following guidelines in defining consumer parameters:

• Add a Title and set the Units properties in the Parameter General properties for each standard and consumer parameter. Most parameter display styles are more usable if they have a title and a units legend.
• Set the parameter's History Level option to Inherited. The setting for the retention of historical data should be a user configuration issue rather than a development decision.